ok i have an st170. im new to it because i used to own a escort rs turbo

im looking at getting an exhaust.

i just want one that sounds nice and helps slightly with performance (by the way im not stupid and im not expecting 5-10bhp gains etc etc lol)

but i dont want a decat because that just pisses about when coming to have MOT DONE u know what i mean.



so CAT BACK OR BACK BOX????

and POWERFLOW (CUSTOM) or ?????????

thanks guys