hi guys. right i have just paid £150 for a 100watt subwoofer which is a factory fit. Since then i have been thinking...is it really worth it? i mean you can buy proper 1000watt subwoofers for that sorta money. so i just have a few questions. If i was to upgrade the sound system would i invalidate the warranty? secondly anyone know any people in the north-west area who specialise in Fiat? cheers in advance