Depends on what you're going for, really. 35hz should be fine for most people's daily setups.
So instead of banging out my whole build at once, I think I'm going to have to do it in stages. It's too cold and I don't have time to completely re-wire everything at once.
CTX65CS components with the included passive crossovers
Amped by a JL 360/2
Stock rear speakers on HU power
Hifonics HFXR active crossover
CTX6M (mids from the CTX set) in the rear speaker location
CXS mids powered by JL 360/2, tweeters by Arc FD2100
CTX6Ms powered by Pioneer GM5500t
I think at first I'm just going to throw in the HFXR and FD2100 to power the CXS set, then when I get time to rewire everything to my liking I'll throw the CTX6Ms in the back with the pioneer amp.
Unless I can trade my brother for a 4-channel he's got sitting in the basement, which would be ideal for space/wiring reasons