Hmm. Using a 45 SET does put you in a position where your midwoofer specs are important. One of the most popular drivers I've found is the Delta 15, but it's a little bigger than you're wanting to go. The box must be very large too. The Alpha 10 is surprisingly good for the price, so you might look at them. The cost is so low you can buy two just to find out if you like 'em or not. If they don't satisfy, you're still only out the price of a tank of gas. And they go real deep and sound pretty good in the mids, so you should give 'em a shake.I'm fond of the 22xx series JBL's, but the under-two-watt situation and the certainty of iron that may not like Zmax fluxuations makes them iffy. Their impedance peaks at resonance aren't real high, but they aren't low either. Same with the newer Eminence Magnums, and with them, only the new Magnum 12 will get you up high enough to consider as a midwoofer. It's good stuff, but you need a little bit of oomph to drive them, and I'm not sure I'd pair them with a 45 amp. It would sure be nice to try these options though.