So I can’t decide whether to go with renntech downpipe or a 63 system? I am hoping this will work...this will be the last thread I ask for any advice or help as my next thread will be what progress I have been making.

Looking it seems the 450/550/63 all share the same cat/downpipes setup. Only diff is the muffler on the 63.

I added RADO downpipes, wish i had gone MBH just bc I had them on my E55. Also removed the resonator and added h-pipe.

I am looking to swap out the 450/540 mufflers for 63 mufflers. Have factory buddy checking on just the muffler part number. Online the 63 exhaust is from cat/downpipes so no way to get just the mufflers which is the only difference. The 450/550 can get just the muffler but 63 is the whole system from cats/downpipe back. Shipping has to be $$$.

So I would skip 63 system as it’s just a muffle and it’s iust sound really. Go downpipes if looking for gains plus some sound. Before h-pipe and resonator removal you could really hear turbos more. Now with all that and tune, sounds like a Ford F250 turbo diesel as for the turbo sound.