The 15W1200 has a -3db point of about 85Hz in PiAligned cab, which is really a bit too high I guess. The Omega 15 in a PiAligned cab has a -3db point of 65Hz. Both drivers though are capable of over 120db - the Delta seems the only one with less SPL output. Omega costs AU$570 though..... Unless I provided some equalization in the highpass crossover (sallen key) which would bring down the -3db point a bit, but I dont 'really' want to do this.

Looks like I got a lot of deciding to do, GRR!