Hi all I'm thinking about modifying my exhaust due to how loud it is. Not entirely sure on the system looks like 2 3/4 or 3 inch pipe with a pre muffler and cat with an enormous glass back cannon. Volume isn't too bad except when the engine is under load or crusing at certain speeds, going up hills etc and it hits a very deep bass note that reverberates in the cab, gives you a headache after awhile.
Willing to suffer s few HP losses in the top end, but not much! Mechanic who does a lot of Subaru Performance stuff wants to measure it up, I know its not as simple as wracking any old muffler on.
My question is will he be able to do a reasonable job with out a dyno? I know he 'street' tunes and then hires the dyno afterwards but should I just go to the place with an all-wheel drive dyno?
Also, am thinking of putting a different ecu later on and adding another 50-100 bhp, not sure if restricting the exhaust a bit will be a problem later on.
Currently running - ST185 with a ST205 motor, FMIC, extra volume fuel pump, Garret Disco Potato Turbo, stock ecu.