Does anyone have the exhaust specs for the B58 engines over the years?

From the early 340is, to the 340i MPPSK, to the switch to the M340i and X3/X4 M40i?
--Is the MPPSK exhaust optionally available for the 340i the same as the "M Performance" Exhaust that comes in the M340i and X3/X4 M40is?

(Obviously some of the European models get the particulate filters, which I believe are just integrated in to a single can with the cat.)

Did anything change with the move to the 382hp TU1 "O" engines in the newest M340i, X3/X4 M40i and the Supras vs the 355hp TU1 engines on the exhaust front?


-I'm interested in the exhaust diameters (stock inlets and outlets of major pipe sections, etc..) and # and type of any cross overs, etc... Just curious at what power levels the various exhausts become a bottleneck.


I believe the 2020 Supra's stock downpipe starts at 4.5" diameter off the turbo and the exit is 3.15", which connects to the stock Y pipe which goes from 3.15" to dual 3" exits. Extreme Turbo Systems offers a 4.5" -> 4" downpipe and a 4" oval -> 3" dual exit Y pipe.


-Going from the 4.5" inlet on the downpipe down to 3.15" to transition to the "Y" and on to dual 3" never made any sense; that 3.15" section looks to be a huge bottle neck in there. I'm guessing it was because a 4" round tube wouldn't fit in there and required a small section of expensive 4" ovate tubing (that's what ETS used). -Just curious at what power levels that 3.15" section becomes a problem.



-I just haven't seen any comparisons between the stock exhausts and the MPPSK was always quoted in terms of HP differences after the exhaust AND a tune, which obfuscates the performance benefits of the exhaust alone and never included a discussion about what actually changed vs the stock exhaust in the early 340is.


Adam