FWIW, if you do end up needing a filter/isolator (I did, because I didn't want to spring for a DC-DC inverter), use the PAC SNI-1 and not the Radio Shack. I did some frequency tests with a RTA and determined it had 0 (!) affect from 25hz (my lf cutoff) to 19.5kHz (the highest the microphone on the RTA would measure reliably).

Oh, and if you can, Junk the becker, it's way more headache than it's worth. If I had it to do over again, it'd have been the FIRST thing I ripped out and I would have more hair left.

PS: Neo, out of curiosity which inverter did you end up with??