Sub to match PMC TB2+

I'm looking for a sub to mate with my TB2+ speakers. I have the TB2's bi-amped and bi-wired to a pair of ATI 602 amps. In front of the ATI's I have a Musical Fidelity X-10v3 Tube buffer. I use a NAD 320BEE integrated as a pre-amp. CD is Musical Fidelity X-RAY.

Room is approx 12 by 17 with a lot of listening done in an adjoining room which makes the distance from speakers to ear about 20 -25 feet. I love the sound of this setup although I'm sure it could be better. The main thing I think may be lacking is the low end. The TB2's do a phenomonal job on the low end considering their size but I can't help but feel that I could get more out of my music bass if I added a good sub. The PMC sub's a way too expensive for me. I'm considering picking up a Sunfire True EQ. Does anyone have any comments on the potential for this type of setup?

I listen primarily to rock/blues/jazz
Post removed 

Considering your speakers it is not surprising that you find a quality matching sub prohibitively expensive. Low frequencies are that much harder to reproduce without excessive distortion (20% and much more at the higher SPL levels which your speakers are capable of). Consider that a lower quality sub or a mis-matched sub may cause you to lose some of the advantages of LF clarity, dynamics and balance that you get from your monitor speakers.
Altho its large and a bit expensive, I love my SVS PB12 Ultra in conjunction with my TB2+ 5.1 system. crossed over at 50Hz, sounds great with movies and music. I've heard the PMC TLE1, and the SVS destroys it at a cheaper price. the only issue for most people is the size...