[MattG]

I think Ace's point is that the car's so noisy, there's no point in stressing too much about getting the perfect sound system - none will sound very good in these cars.

I'm running a stealthbox off a small Blaupunkt amp, with Polk speakers replacing the stock ones and still run off the head unit. It sounds great and is a simple, relatively lightweight solution. Upgrading speakers alone didn't make much difference IMO, what really did it was adding the subwoofer.