which exhaust??
 

Please can i have some advice on which milltek exhaust to get between a Non-resonated and a resonated it will be cat back. It will be going on 2002/2003 subaru sti.Has any one got any of these if so what are they like ie noise level and power gains any advice whould be greatfull thanks in advance

Go for non resonated for a bit more noise, especially if keeping the cat

why is the non resonated cheaper?

Because it's cheaper to produce as has no resonatoer welded into the straight section of pipe.

are the noise levels that different as i dont want it too loud?

Normally only about 1 - 2dB different.
If you still have a cat or get the sports cat this acts as a good silencer, so no real need for a resonator. Especially on the MilTek which is one of the quieter stainless systsms anyway.

I'm running the full 3' sports cat Milltek system and had a noise test at 91dB at Goodwood, personally if you are thinking of changing the exhaust get a full system, there were a couple on scoobynet around £400 recently.