The front speakers are 13cm and the rear are 10cm I believe.
The best setup with some decent sound on a budget would be 13cm coaxs up front and 6x9s in the back all on a 4 way amp, then set a high pass filter (around 80-125hhz) on the front speakers (should be able to set this up on the head unit or amp).
You can upgrade to components int he fornt but generally cost more and can make sound staging worse.
I would recommend (clicky)
You will need a headunit with at least to sets of preouts for this.
But overall I would say the above setup will give you good results for not much money. I was running those 7x10s with no subs for a while and everybody thought I had subs running.
As for wanting all infinity, if you was entering competitions and wanting huge specs go for it, but for a smaller budget system there are other brands (like listed above) which are good quslity and great value.
I can fit about 5-6 tescos bags in the boot. One medium suitcase or a small midget - if you were so cruel. When I run out of space, i utilize the back seat! I highly doubt you'll get it sounding good - on a budget - without a sub.
