[kfardan]

The stock LPFP was able to handle 600WHP on E50 without issue, but not sure how much further it can go as there are no LPFP sensor on N55. But I think at 650WHP you will need to upgrade the LPFP.

You only need the crank hub fix if you planning to push close to 700WHP in which you will also need fully built engine to do that safely. Furthermore the ZF8 gearbox also at the limit at 600WHP+ specially the 6th gear is weakest on the transmission. It will not be able to handle more than ~550WTQ on 6th gear anything more and it will slip.

I personally using Dorch Stage 2 HPFP ... super happy with it. No complain. It also work with Bootmod3/MHD without the need for a special tune. But Spool HPFP FX-180 is also a good option and flow more than the Dorch (1.465 vs 1.6) the disadvantage is that it cost more and need a custom tune in order for it to work.

The kit comes already with catless downpipe. If you want faster spool and more power then stick with the catless downpipe. If you have stock exhaust it's not that much louder than stock ... make sure to disable cold start and you are set.

For the Intercooler you can go with VRSF 6" or Evolution Racewerks.

While doing the turbo installation since you will need to drop sub-frame it's good idea to replace the oil pan gasket as preventive maintenance (Usually it's start to leak after 4+ years use).

My recommendation to take things slow to make sure everything is working properly before fully pushing it to 650WHP. Good luck.