Re: Aftermarket exhausts
I had a Group N OMP zorst on my last 155 when I bought the car. Fantastic at high revs and under load, but very loud and a bit annoying. Took it off and put an OE system on.
Had a Powerflow on my Silverstone and V6 155's. Was OK for noise as I got asked how loud I wanted it. Got a 2 box instead of 3 box system fitted to them.
Stainless steel, but cheap as chips. My boxes on bith cars started rusting within about 6 months. Fixed under warranty and the cars were sold. The dealer no longer does Powerflow as he said the boxes were crap and he had so many warranty repairs 'cos they rusted. Now uses a different make of system, can't remember the name though.
I would go for a "proper" zorst like Supersprint, Ragazon or CSC. Guys that have tested the zorsts for best performance. Remember a custom zorst isn't made for your engine, it's made to fit the car, so I would say not as good as the "proper" zorsts.