To avoid poor energy transfer (caused by filter chokes that limit amplifier dynamics) only a regenerator will do. The PS Audio Power Plant Premier sucks IMO (and it's not big enough for your needs anyway). APS PurePower now makes a 20 A model
http://www.purepoweraps.com/pdf/2000%20tech%20specs.pdf and Exactpower will be introducing a 20A model next year.
I'm waiting for the Exactpower because it uses patented technology that only fixes the out-of-spec parts of the AC wave (never more than 20%) instead of throwing out the baby with the bathwater and starting from scratch; which is the old (and highly inefficient) way of doing it (PC Audio PPP, and APS PurePower.)
Everything else is useless crap IMO -- especially with an amplifier(s). (BTW, Furman is now owned by Panamax, and isn't much better!) Another thing people don't usually realize is also that voltage regulation is essential for maintaining tube bias in tube amps. You can get equipment to do this separately of course, but the APS and Exactpower have that built in, along with surge protection that really works.
A word about surge protection: most modern equipment will have built-in surge protection to protect it from the kind of "day-to-day" surges in our aging power grids. That's all that units like Furman, Panamax, Monster, Richard Gray, Shunyata, and all others can provide; so in that regard, thay are ALL redundant! For REAL surges, that can do REAL damage (like lightening, or utility start-ups after power outages) VERY FEW units will protect you. The coming Exactpower will, but if you really want to be safe, unplug your system when a thunderstorm approaches or when you go on vacation.* In addition, if you live somewhere that has lots of power outages, you had better get yourself an in-rush current limiter for your system at the very least, and if it were me, the whole house!
* And don't just "throw the breaker" at the panel. Lightening has been known to jump right across an open circuit breaker trying to find a path to ground (usually right through your equipment!)