anybody using subwoofers and/or isolation bases for their Fore III's?

how is the T9 working out?  can it keep up with the bass output of the forte's or does it just augment them?

Op, 

Yes, I use an REL T9 with my Forte IIIs and I use a Auralic Subdude on the sub.  Both are great in my room.  I haven't tried a subdude under the speakers.  Do they make one large enough? 

I'm assuming you mean "Forte" IIIs. I use Vibrapods under my Heresy IIIs and those things really work...the "pods" have felt pads stuck to the underside to make the Heresy IIIs easy to slide around when trying various positions or cleaning the floor. I've used 2 REL subs for years (Q150e, and Q108MK2) that sound great and are adjustable to a degree that you can easily tailor the output and phase, etc.