nah, ya don't *need* subs w/the 3.6's, yust, imo, i'd rather have *that* set-up than a pair of 7's. when i had my thiel 3.5's in my main system, (due to electronic equalization, these are actually flat to 20hz), they were definitely improved w/a pair of vmps larger subs, x'd over at 70hz. i was able to lose the equalizer, too. the bass was tighter at volume, and the mids & highs were also better - less stress on that 10" driver, and losing the equalizer both helped.
regards, doug