Pioneer comps are efficient, but yes they have little watts... but, that doesn't make them quiet. I mean, if Bose can get a 5watt wave radio sufficently loud... then I'm pretty sure Pioneer can get a good pair of components very loud.
Personally if it was me mate, get this:
http://www.caraudiodirect.co.uk/product_info.php?products_id=4723&cadid=e5ea7e7c49b39688a19170d86f9d7371
and...
http://www.caraudiodirect.co.uk/product_info.php?products_id=4140&cadid=e5ea7e7c49b39688a19170d86f9d7371
Rig that up, and you'll have some serious high/mid end... and quality sound as well...
However, dont forget to look up the big 3 and get yourself a good battery...
Fusion probably are crap, specially if it's less than £50 for a set of speakers - but it's subjective, you may like them.
If you want deep, powerful, low bass... and I mean LOWWWW then RE audio are the complete best. They have mad excursion, that no Sony, even Alpine, JBL or anything else can match... these are true monsters. They have a new range coming out april.. so look out!
RE's excellent amp...
http://www.caraudiodirect.co.uk/product_info.php?products_id=4322&cadid=e5ea7e7c49b39688a19170d86f9d7371
www.bladeice.com < Contact the guy at BladeIce about the XXX's they are expensive... but man they have SERIOUS power. I mean, it is serious.
Don't laugh at it's 2000watts, it may seem little, but these beasts kick out more than anything else. It's a real 2000watts, remember other speaker manufacturers have to lie to compete... with peak, max power, etc. This is Normal Power Handling. Those RE xxx's can now handle 3000watts, no problem.