Just testing the waters to check what price would be fair to ask for a used 20-39PC. This unit was purchased new from SVS by myself and has recently had the "improved" driver upgrade and also the amp upgrade (to 325 watts I think). Transferable warranty of course.... This unit has been periodically calibrated as I change out other items in my HT system often. And YES, I have driven this great sub to its limits......with never a problem except with the neighbors. It's being used in a 3100 cf space and provides all the shake we've come to love. Even though I'm moving to a PB2+, I have a hard time imagining it being THAT much better...... When I figure a price to ask, I'll put it in the Used Subwoofer area......Thanks for any input.