I'd think a bit about the Quadra + Expander + Maths all in the same rack, as Quadra + Expander will duplicate a lot of Maths functionality. They'll match really well together, I think, but unless you're looking to do complex west coast generative patches you don't really need 6 LFOs / EGs to control a DPO. Of course you could get both and sell whichever one if you don't need it though, which is the best way if you can afford it.
-- chartrekhan
He would need to clock the a-149, control two channels of optomix, 2 channels of vca and several dpo destinations, let alone modulate the modulation with self patching. Plus, Maths has the ability to slew/process/mix cv as well, so it can often be used for many things other than LFO/envelope generation. Also, given his module choices, it seems west coast complexity IS what he's going for.