What are you doing for REAL subs?
Buy the 8060 and spend that extra $1k on a big boy sub-woofer!
Even better, stick with the 9020 and buy a PAIR of big boy subs!
Seriously, those built in DT subs cannot compete with a real sub. They are fine for almost all types of music, except maybe some of the deepest digging hiphop, but for movies, you will NEED a sub-woofer.
For reference, I run a pair of GE T2 (they share a heritage with DT, and they also have the built in powered "subs"), but I run mine with a Rythmik F15HP.