This is the stealth system that i had in mind.
USB only radio <no CD> hidden in cubbyhole
4 Infinity Gold speakers from a Jeep Cherokee - they have a freakin' awesome sound system as standard

1 removable bazooka bass tube with an 8 inch sub
1 small amp to power the above.
Antenna hidden in rear window.
Looking at the car, you would never say that there is a system installed.
That's about it.
I listen mainly to dance and mild trance like ATB, Derek The Bandit etc, so i don't need a super thumping system.
We did a similar install in a mate's golf vr6 using Bose speakers from a merc and it played brilliantly!