with the rest of ur exhaust, on the 20v's i use this system,i made about 10 kw atw and picked up a heap of midrange torque
i had stainless extractors,jasma spec, that came with the car, they were 4-2-1's, and ran a 2.5 outlet, from that i went into a 2.5 inch cat then cam down to a 2.25" inch pipe to a 2.25 muffler then on the other side of that up to 2.5 the rest of the way.
my theory is that, is has enough room to collect,enough flow thru the cat, then can pick up velocity thru the smaller pipe and muffler till it cools down ad goes thru the 2.5 (bigger allowing for more flow, cold exhaust gas flows slower than hot, from what ive been taught anyway)
seems to work well might be an idea for u
The TODA manifold is $1450... the rest of the exhaust is $1060 but that doesnt include a catalytic converter... TODA "race cat" (straight piece of pipe lol) is $295 and is not legal for road use obviously...
This is a quote from TODA Aust.
Cheers
Daniel