So, I'm building a Tele, and have already ordered a Fishman VT Powerbridge for it, and wanted to go as stealthy as possible, and therefore am going fully passive installation (no battery/controls on the guitar for the piezos, switching/blending will be done on the pedalboard) and have been looking at outboard pre-amps. I saw the Fishman Aura and liked the sounds of it plugged into an acoustic, but this video really sold me on it for my purposes
[VIDEO]http://www.youtube.com/watch?v=eMlUDgOKyN4]YouTube - Fishman Aura 16 Using Electric Guitar With Piezo[/VIDEO]
(and yeah, I've already checked and it'll work just fine with a passive piezo pickup)
I did the same thing you are trying and I would highly recommend getting the Spectrum DI because with out the body of the acoustic a lot of the tone is missing (my tele is a thinline to boot) The spectrum is a DI, EQ and compressor all in one and IMO the aura system in conjunction with and electric really needs it.