Hey mate welcome to UKSC Off the shelf exhausts are not cheap for sure but worth every penny, you could always go the custom route where you could get a cat back system for under £300 To ajust the damping its the little screw on top of the strut which you wind up to get it soft or wind it in to stiffen it, cant remember off the top of my head which direction is for which but it reall doesnt make alot of difference anyway There are different springs available for them with softer spring rates, hope this helps ;) Pics!! ;)