[Kaps335i]

I have a 2013 335i xDrive. I was going to order the Bilstein B8's with Dinan sway bars, and Eibach springs. Apparently there is a long ETA to get the front struts from Bilstein. So now I am thinking about the KONI Sport (yellow), which are in stock.

How would you compare the two?

[skier_du]

It's been a while, but I have experience with both Koni Sports and Bilstein B8 (albeit on 2 different BMWs). I would say it depends on your specific goals with your car and the type of roads you will be driving. I live in the NYC area and drive xDrive, so I have (like you) less suspension travel in the front than a rwd BMW. I prefer the feel of the Koni over the Bilstein. Bilstein is still leaps ahead of chasis control and refinement over factory. However, they are a bit hard at initial impact. On large bumps (which there are many here. Heck, I think most roads are just a series of potholes) they are hard initially, then go too soft and the bump goes right through them. The Koni has adjustable rebound, which means you can match them to the spring you run. They are initially softer, which is good for small bumps and continuous, broken pavement, where the Bilsteins feel like they skip across some; meaning the Koni will keep the tire in more contact with the pavement more often here. Also, they do better at absorbing the larger bumps.
Driving impressions aside, I believe if you want to lower your car much more than an inch, the Bilstein B8 will have more suspension travel. They are designed to work specifically with lower springs that will lower the car about 1 inch or more (I talked to a tech at Bilstein about this). If the B8 is used with a factory spring or anything that lowers less than an inch, it can actually ruin the shock. If you do not lower the car at least 1 inch, you have to go with the B6. Also, the Koni Sport is not designed to work with anything too low, roughly 1.5 inches or less, I believe.
So, in the end, Bilstein B8 for lowering, Koni Sport for a nicer ride, possibly also better performance.
A tip; if lowering anywhere near 1.5 inches or more, cut the internal Bilstein bump stops, or get shorter and slightly firmer ones for the Koni Sports. Even if only lowering about 1 inch with the Koni, I'd still get shorter front bump stops. Some people suggest the E36 M3 front bump stops, but they're not short enough for the xDrive. I used the shorter, and firmer, Speedthane bump stop on my Koni Sports. I believe I even trimmed them a few mm's. That worked nicely.

[brigade24]

Originally Posted by Kaps335i

I have a 2013 335i xDrive. I was going to order the Bilstein B8's with Dinan sway bars, and Eibach springs. Apparently there is a long ETA to get the front struts from Bilstein. So now I am thinking about the KONI Sport (yellow), which are in stock.

How would you compare the two?

true...bilstein will take forever and koni's don't have enough compression but depends on the spring rates of the eibachs.

i have the exact same car and i just installed BC Racing coilovers for about the same money...I believe they are around a thousand dollars US for your car...plus you can pick your spring rates which allows you to maintain the factory handling characteristics (flat ride) while going with stiffer springs.

[Issa.M]

Originally Posted by brigade24

true...bilstein will take forever and koni's don't have enough compression but depends on the spring rates of the eibachs.

i have the exact same car and i just installed BC Racing coilovers for about the same money...I believe they are around a thousand dollars US for your car...plus you can pick your spring rates which allows you to maintain the factory handling characteristics (flat ride) while going with stiffer springs.

How have the BCs been for you? I've heard mixed opinions

[casualDIYer]

Originally Posted by Kaps335i

I have a 2013 335i xDrive. I was going to order the Bilstein B8's with Dinan sway bars, and Eibach springs. Apparently there is a long ETA to get the front struts from Bilstein. So now I am thinking about the KONI Sport (yellow), which are in stock.

How would you compare the two?

Can't comment on the Bilsteins as I have not tried them on my present F30 but the Konis are fine. I paired them with ACS springs. On the street the ride is similar to the M Sport suspension. You feel bumps but it's not intolerable. A couple of takeaways though as I had to go through a process to get them where I liked

a) I used the Dinan supplemental ride kit (i.e. the famous E39/E60 bumpstops) in the front but used the F80 bumps in the rear. For city driving there is little difference since the rears rarely engage the bumpstops but on the track, I didn't want the bumps engaging too late with the Dinans, which are shorter than the F80 bumps. I stuck with the F80 bumps for the rear. For the front, using the Dinans eliminated 'crashing' when hitting pot holes as the strut could travel further before bumpstop engagement. I could have cut the F80 stops but . . .

b) I set the rebound to 1/2 turns from full soft on the fronts (for city) and set the rears to 2/3~3/4 turns from full soft for the rears. Setting the rebound to a slow (i.e. stiff) setting, you feel all the undulations in the road.

On the track is where the difference between the non-M suspension (that came with the car) and Koni + ACS springs really made a significant difference. On OE, I had to hold onto the steering columns for dear life in a turn. One could get motion sickness. On the Konis, set to 1-1 1/2 turn from full soft, the body is far more stable, confidence is higher, and lap time improves by 4 seconds. In general, chassis control feels more precise on the Konis + ACS

Wish list:
a) I wish I could set the compression. Having the Konis a little softer in the city would be nice.
b) a faster way to set the rear rebound.

Finally: Like you, I too initially wanted the Bilsteins but no product. Went for the KW SC, and again, no product. The Koni + ACS was reasonable price wise and available and turned out to be a preferred setup over OE. If I were to try again, I might go for the ACS dampers, which are a custom valving of the Bilsteins, or bump up to a KW V2. Or just go for the Ohlins but the price is pretty high comparatively.

[cfm56d7b]

Originally Posted by Kaps335i

I have a 2013 335i xDrive. I was going to order the Bilstein B8's with Dinan sway bars, and Eibach springs. Apparently there is a long ETA to get the front struts from Bilstein. So now I am thinking about the KONI Sport (yellow), which are in stock.

How would you compare the two?

What's your budget for the suspension upgrade? Are coilovers under consideration?

[equalee]

Originally Posted by casualDIYer

Can't comment on the Bilsteins as I have not tried them on my present F30 but the Konis are fine. I paired them with ACS springs. On the street the ride is similar to the M Sport suspension. You feel bumps but it's not intolerable. A couple of takeaways though as I had to go through a process to get them where I liked

a) I used the Dinan supplemental ride kit (i.e. the famous E39/E60 bumpstops) in the front but used the F80 bumps in the rear. For city driving there is little difference since the rears rarely engage the bumpstops but on the track, I didn't want the bumps engaging too late with the Dinans, which are shorter than the F80 bumps. I stuck with the F80 bumps for the rear. For the front, using the Dinans eliminated 'crashing' when hitting pot holes as the strut could travel further before bumpstop engagement. I could have cut the F80 stops but . . .

b) I set the rebound to 1/2 turns from full soft on the fronts (for city) and set the rears to 2/3~3/4 turns from full soft for the rears. Setting the rebound to a slow (i.e. stiff) setting, you feel all the undulations in the road.

On the track is where the difference between the non-M suspension (that came with the car) and Koni + ACS springs really made a significant difference. On OE, I had to hold onto the steering columns for dear life in a turn. One could get motion sickness. On the Konis, set to 1-1 1/2 turn from full soft, the body is far more stable, confidence is higher, and lap time improves by 4 seconds. In general, chassis control feels more precise on the Konis + ACS

Wish list:
a) I wish I could set the compression. Having the Konis a little softer in the city would be nice.
b) a faster way to set the rear rebound.

Finally: Like you, I too initially wanted the Bilsteins but no product. Went for the KW SC, and again, no product. The Koni + ACS was reasonable price wise and available and turned out to be a preferred setup over OE. If I were to try again, I might go for the ACS dampers, which are a custom valving of the Bilsteins, or bump up to a KW V2. Or just go for the Ohlins but the price is pretty high comparatively.

Hard to find people with experience on ACS... I was set on ACS springs + dampers, but recently have been looking at Koni Yellow + Dinan or ACS Springs — thoughts on those options?

[casualDIYer]

Originally Posted by equalee

Hard to find people with experience on ACS... I was set on ACS springs + dampers, but recently have been looking at Koni Yellow + Dinan or ACS Springs — thoughts on those options?

I've been on the Konis and ACS springs for more than a year. The ACS springs are very good. There is a lot of positive comments about them and I think the accolades are well deserved.

The Konis though, I find the pairing with the ACS has been a bit too harsh for city driving. I have made changes to the bump stops (Dinan in the front and F80 M3 in the rear) and drive on go-flats instead of run-flat tires but I wish the Konis were a little easier on sharp small bumps. The highway driving is great. The track driving is great. City driving is where the setup struggles.

I know ACS has a rebadged-Bilstein damper + ACS spring combo you might want to look at. I had considered maybe going with the ACS/Bilstein damper but have been unable to track down a retailer who will sell me just the dampers. Not too crazy about buying a second set of springs.

I'm thinking for next year, I may switch to a KW Street Comfort or V1 if I can't find a solution for the Koni's harsher ride on city streets.

Please keep in mind, these comments refer to where I live. Others may have a different experience with Koni in the city they live in.