Hi just fitted my sub and amp from my old car to my sti8, all is fine untill i turn the volume up half way and then its as if its getting massive feedback and just buzzes like hell, i know it isn't the earth as ive tried in a few good places, and it cant be the amp as it worked fine in my old car, and i also tested a different set of rca leads used for the front speakers, only thing i did which i think could be causing it, is that i ran the power cable down the same side as the rca lead, anyone know if this would cause it??
dont really fancy taking all the trim and carpet up if this isn't the cause.

 

From past experience, i would have said that running the RCA's & power cable together is the source of problem. I thought it was one of the rules of any install that signal & power cables should be kept as far apart as possible.

Good luck - hope you get it sorted.

Mike