Our 2010 F150 came with a SYNC, but the stereo itself was pretty crappy. The stock door speakers can't handle much, probably due to the anemic amp in the stock deck, so the plan was to take some parts we had laying around and fortify the low end.
A cheap truck wedge box from Parts Express, a spare Kenwood 10" sub, an old 50 x 4 Sony Xplod amp, and a Audiobahn AKIT4J from this site, and we were in business. Without hacking any of the factory wiring, I was able to pull out the stock head unit, plug this adaptor in line with the factory harness, and I was in business with two sets of preamp outs to run back to the amp. Worked like a charm.
Not many features; just simple addition of preamp outs with level adjustment for cheap. I would recommend this to anyone with a modern Ford stereo that doesn't feel like hacking up their wiring to put a LOC in their car.