[Jamie]

The sub provides the punch and will easily be capable of what you want.
Setup properly you might find the seperates system to lack a little initially compared to your all-in-on, It shouldn't take much listening to realise its much better but quite a few people mistake loud, muddy bass for quality.

I've yet to hear a AIO system that didn't have the Bass turned up far too high and been clearly able to hear where the sub was, my mums Panasonic had to have the Bass level turned right down to minimum setting to sound OK. Setup up right you shouldn't be able to actually hear the sub, the key phrase here is integrated. You can always turn up the gain on the sub though if you wish