I bought and installed a set of VAP 200 cell downpipes. The car became obnoxiously loud getting on it in dynamic mode. Tone is very raspy at higher rpm’s. So, I’m welding in some resonators to tone it down a little. In hindsight, I should have just ordered the resonated version VAP sells.

I noticed VAP’s downpipes are identical to stock in terms of how they fit and tubing diameter. Tubing is 60mm OD and where they merge into the stock system they neck down to about 50mm.
The exhaust system goes from 60mm to about 55mm at the mid-pipes and necks down in two spots to 50mm for the clamps.

I’m know stock exhaust systems are highly engineered for performance, flow, sound, packaging, efficiency, etc. For such a high performance vehicle, necking down the exhaust to about 2” at the mid-pipes, and again near the muffler suitcase, seems counterintuitive.

What do I have to lose by going full 2.25” from the mid-pipes to the muffler? I would keep the cross-over in the same place, it would just be changed out for 2.25” as well. I would just hate to mess anything up as far as low end torque, exhaust scavenging, etc. On the other hand, 2” OD tubing in some spots seems really small for a higher horsepower car.