Currently im running a sony XPLOD 12inch sub woofer and soft Pioneer speakers which i got on the cheap, The problem is my sub ways a tonne. Is there any speakers that give a similar bass to a sub that dont cost the earth? I love my music and like it sounding complete. And if its possible alpine would be prefered to match with my HU. HELP PLEASE.

Trouble is mate, if you want good thumpy (technical term ) bass you need to amp the speaker/sub.

I can get some nice 8" InPhase subs, i'm waiting on updated prices for these at the moment. As for Alpine etc, i'll be honest i can't compete on price with many of the net dealers out there for that line.

So say if i got a 8inch sub or 2 (maybe) and mounted them in the rear passenger side panels would that help with the weight, plus would it be possible to mount them in the side panels? Obviously with work and possibly fibreglass

short answer - yes

See my group buy thread