I'm looking at upgrading my old Kenwood amp to something which has support for more sound formats (DTS/DPL2 etc). I was looking at something like the denon 1905, but i might be tempted into importing a yamaha 750. I'd like to keep the current speakers (also Kenwood) for now at least but the thing is that they use a passive sub (built into the front speaker cab), so i'd also be up for a powered sub. I didnt want to spend huge amounts of money, but something in the £200 region should be ok (e.g. the MS309?). Any thoughts in this? I'm also wondering about upgrading from 5.1 to 6/7.1. Initially i just thought i could get an extra set of cheap rears, but now i'm thinking it might be better to get some new fronts and rearrange my existing speakers. Anyone have any ideas on a good upgrade path? f.y.i, the current speakers are rated at 100w/6ohms, and the rears are bipolar.