i put a diamond Audio TDX 15 in a custom Fiberglassed enclouser in my Friends 99 CSVT and i had a Stroker 15 with 2k wrms in My 98 CSVT and at another time 4 Kove 12inch armeggedon X's with 2k wrms....
The rattles will never ever goo away. if you have a spoiler its pretty much something you have to deal with. I got my friends 99 kinda quite but the subs still breaking in
