The 15" driver in the 735 has a 3" voice coil whereas the 15" driver in the 745 has a 4" voice coil - so more beef. They share the same sized HF driver (on cursory reading of the specs). Has anyone got any experience of A/B ing them in the real world? The crossover point is only 150hz difference which at 650hz and 800hz is (and I am TOTALLY guesstimating here) perhaps a major 3rd so not HUGE in the grand scheme of things. My GASeous nature always drains my finances and that would cost me an extra £300+. I am not actually going shopping tomorrow, this is just a storing info thing. However, for a speaker which appears to be ALL THAT, why are they both so ugly? Someone has to design them from scratch, so why not make them look like they cared for aesthetics. There is a whiff of Transformer about them.