So I've got a Polk Audio RM6750 5.1 setup in my family room with a Yamaha 8" subwoofer  that replaced the original Polk sub that failed on me all running off an Onkyo SR304(don't laugh it's the best receiver that will fit heightwise under my wall unit) , and I'm reading all the glowing reviews and comments on the Aperion forum and AVS Aperion owners thread and I've got a question.

How much of an upgrade will it be moving from the Polk Rm 6750's (I need to keep the Yamaha Sub because it's the best 8" sub I could find that will fit in a tight spot on the front wall of my family room in the corner - sadly I only have a 12" width clearance) to a 5.1 setup with (4) 4B and (1) 4C?

I watch 70% TV, 25% movies and 5% music that consists of XM Radio on Satellite TV and Metal Mania on VH1 Classic (go hairmetal!). If the 4B's are that much better than my Polks I may listen to a lot more music than I do.

For the record I'm pleased with the Polks for movies, but they really sound thin to me for music so I thought about getting (2) 4T and (1) 4C and (2) 4B's for surrounds. I used to listen to music on some old Cerwin Vega 500w towers that had a 10" speaker that sounded great, but the WAF got so bad I had to get rid of them last year.

Is it worth the $680 for (4) 4B's and 4C since they're so similar in size to the Polks, or should I fork out the $1070 for the 4T, 4B and 4C and sacrifice the sub (which doesn't thrill me for TV and Movies)?

If you're going to suggest getting big towers to make up for the sub, I can't go any bigger than 5T's for space reasons and if I do I don't have room for the sub.

What to do?