[spielnicht]

Recently sold my pristine E85 Z4 3.0si and had wanted to replace it with an E86 Z4M, but looking at other options now since finding one and at the right price, seems to be tricky. All my life, I’ve been in love with 3 BMW models: E31 850i, E39 M5, and E86 Z4M. I see myself owning one of these as a forever garage queen, savoring every minute invested in working on it. It won’t be always garaged - I’m buying it to drive and enjoy.

If it comes down to an E31 850i (manual) vs E39 M5, which would be the better forever BMW? Better in appreciation? Keeping it runnning? I will never say no to the M5’s performance, but an E31 shines in its own way. Any advice is appreciated.

[TriumphTim]

E39 M5 will probably be easier to source parts, they are awesome cars.

E31, I have driven and maintained an 850i auto. Has steering box which felt more loose to me, kinda floaty even for a BMW. Not really fast, the E39 M5 felt much faster, revved more freely. Might be a long way off from a Z4 in terms of handing, weight, and quickness.

The M5 also has a steering box but the one I drove was very tight even at 100k miles, unlike the E31 with less miles, might be car specific according to wear and mileage.

I would probably recommend M5 overall, manual E31 would be fun for sure and maybe better investment due to rarity? I recommend test driving one first, I found the E31 to be more "vintage" in terms of handling and power, where the E39 M5 felt modern but still exciting.

Good luck, have fun!!

[pbonsalb]

I would buy the E39 M5 over any E31. Z4M if you never need to carry 3-4 people and want a more direct and involving car, but you already know that. Since you have had a long run already with a Z4, try something different.

[Elderado82]

Here's what I think: as soon as I see an 850i, 850Ci, or 850CSi, the first thing that comes to mind is I hope you're ready for high maintenance. If you want a queen and don't care about what it takes to take care of her, then the 850CSi and only the CSi takes the cake. But if you want something that's not going to have you on your knees, then the M5 100%.

[TriumphTim]

Not just maintenance intervals but the part sourcing and costs too for E31, a big job in and of itself, so many fewer E31s were made.

Engine stuff wasn't too bad but body and interior parts can be very difficult to find,

[MJBO]

If it’s forever, what does resale value matter?

The E39 M5 is easily the answer to your question though.

[ppointer]

E39 M5 all day long.

[M5Rick]

Its got to be the M5 E39, a no brainer really.

[spielnicht]

Thank you all for your input. The consensus here is def. the E39. I kind of assumed as much, but the thoughts around E31's looks and rarity kept intruding on my decision.

[TboneS54]

*with a muffler delete

Can't beat the S62

[ShocknAwe]

M5 and keep your Z3.