I use the (now no longer in production) S1 Sub Integrator from Thiel.
It allows me to dial in the subs to work seamlessly with the 3.7s and just about every other speaker I have tried (not just Thiels).
The SS2/2,2s are just dead easy to set up. No mics needed. I just take out a tape measure (hardest part) to measure how close the subs are to the walls on the side and back of the sub. And on the S1 Integrator, I read off the specs from the manual of the power amp (gain) and speakers (sensitivity, ported/sealed, low frequency 3dB limit) and that's it.