One thing that periodically surprises me is how much difference a big-ass power amplifier made each time I added one (this time going from HK 3270 receiver's 65WPC amp to a used Adcom GFA555 at >200WPC). It only allows the volume control to go a moderate amount higher before the clipping lights start to wake up, but that seems to be a very important handful of dB in terms of "slam" or whatever we are calling it these days.
At least with an HT system stacking up big-ass subwoofers gets you most of the way - I was always impressed with how effortlessly John <user name escapes me>'s 4-subwoofer system handled peaks that my system couldn't touch. IIRC he was running a mix of EP600s and SVS's to take advantage of their different strengths and weaknesses... I ended up copying that on a smaller scale by adding an EP500 to my SVS PC+ 20-39 and it does make a very nice difference.
EDIT - lightbulb moment... I was in PEI a few weeks ago and had a nagging feeling there was someone I should be looking up while I was there. Three weeks late, oh well...
I guess I successfully derailed another thread. Sorry about that