just ordered a kenwood kiv-700 a few minutes ago from crutchfield. i got the PAC C2R-FRD1 Ford Radio Replace Interface for $64 because i ordered the head unit from them as well, but it actually costs $125. but i think that is all you need. (i have an 06 gt with the shaker 500)
I was wondering about the regulator also, if you have this wiring harness do you still need the regulator? i don't think you do, but it's only a few bucks and i'd hate to not do it once i have everything out if it is going to pop.