Adam, what system do you have in your car? AS1 (cd head unit) or AS2 (cd/tape unit). I transformed my AS1 to a seven speaker setup that sounds great for about £340 all via ebay, Alpine head unit £95 (new), JBL 4 channel amp (rrp £250, paid £92 new), JBL 6X9'S (£21 2nd hand), Alpine wheel control adaptor £45 new), amp wiring kit (£16 new), install £80 (top fella off ebay). I had the boxed 12" Kenwood sub from a previous install, but you could get one from ebay for about £45-50. If you're electrically competent you could save the price of the install, see the sticky for rudimentary instructions, its well worth the effort.