I would get a 4 channel amp, as it is more versatile and there is more scope for expansion later when you get the audio bug.
Some JL stuff is nice, but you pay a premium for it, there are other makes where you get more bang for you buck.
Any reason why you went for the 8" sub? You could have a 10 which would take up roughly 1.5cuft for a ported enclosure or a 12" which would roughly take up 2 - 2.5 cuft for a ported enclosure.
I would go for something like this:
http://www.caraudiodirect.co.uk/rainbow-slx230-deluxe.htmlhttp://www.caraudiodirect.co.uk/jbl-gto1214.htmlhttp://www.caraudiodirect.co.uk/spl-dynamics-ice150-4.htmlhttp://www.caraudiodirect.co.uk/celsus-cnk4-4awg.htmlRun two channels of the amp to the comps up front and bridge the rear channels to run the sub.
Its a great little starter system.
Remember the golden rule, 90% install, 10% equipment.

Up front on the dash where the original 3.5" speakers are, take them out and put your tweeters there, use a thin metal bracket to align them the way you like, the refit the cover back over the top, it will look OEM but sound excellent.
good luck, any Q's fire away.
