i'll start this by admitting that i'm not a real ICE guru
but anyone with a spider with standard stereo/speaker setup knows how bad it is (+ contending with noise thru hood & windows
so just thought i'd share results of my 'experiments' (upgrades)
my car came with a new sony head unit (CDX-GT121) with 45Wx4 output. seemed like it should be ok with decent speakers
so out went those std tiny door speakers, & in went some infinity 6822cf 6x8/5x7 speakers (n.b. had to dremel the corners off the speaker frame to make fit into the oval door card hole, plus v.slightly open up the speaker hole - cutting back the 'centralising struts' used by std speakers)
with door cards off i also discovered that one of the std tweeters had fallen out of its flimsy plastic retainer & other one was loose!
connected everything back up and....it was still far too tinny
(even with bass boosted to max)
so then i got a single cheapy 6.5" speaker for the sub-woofer hole in the rear cubby (not sure if there was supposed to be a std speaker in there?) from maplin - only £6 - & connected this up to the rear speaker lead (orange/blue) that was floating about in the rear cubby.
result - a little better bass, but still a bit tinny/wimpy
last mod...back to maplin for a cheap power amp (cheapy bass speaker was 6ohm, so head unit prob couldn't drive it too well). sony head unit had sub-out (pre-amp phono connectors on back) so thought i'd try 'em! £40 for 200W maplin car amp which slotted nicely into rear cubby. connected it up and...wow!!!! wot a difference!!
at last - proper bass & rich sound...no tinniness. and std tweeters now complemented the sound rather than adding extra, unwanted treble!
(didn't even need to use bass boost or lpf switches on amp - just running rear speaker as a std full range speaker)