I see you placed an ordered for the Sierra Towers....I hope you like them but judging by your comments on the S2s...I see no reason why not. The term "loose" is not a word I would commonly use in describing the bass on Towers.
I've often found myself playing them at relatively loud levels...I'm a big fan of Tools "Danny Carey" ...if you like his style you'll like the Towers...

. His change of pace, power, kick drum, speed & finesse... it's all there with the Sierra Towers....IMHO
I'll await your thoughts once you've spend some time with them...after you order is completed and shipped.
Take care...Bill