popchargers sound bigphil sells them £95 iirc
i had a bmc cai on my last car and it sounds great, aren't they £200+ ?
the zed ecu is self correcting so no mod really increases performance except maybe a plenum spacer unless you get a piggy back ecu
most mods are for noise or looks
http://www.350z-uk.com/forum/viewtopic ... highlight=