Sensible upgrade from non Bose system

[MrHooky]

So I've had the S8 for about 2 months now and I must admit that the non-Bose system is a bit poor. I've got a 2004 8N TT which has Bose and the sound is much better.

My question is, how easy is it to upgrade the non-Bose? Are all speakers on the Bose system upgraded? Is there a dedicated sub? The Bose in my TT just sounds a lot warmer and has much better base. If I could just get a bit more base I'd be pleased.

Not wanting to spend a fortune but if there's a quick and easy upgrade I'd be interested...