I had Best Buy install a remote start in our '88 E150. Price was great, but the details of the install were poor. Just sloppy all the way around. Most likely, they're not given enough time to do a good job because of the thin profit margins.
I don't know the details of what is involved in the heated seats add-on, but I'll tell you of one problem ours had. After it was installed, it didn't always start the seats. We were told the ambient temperature determined whether they would come on or not. So, we had a switch added, so I could override it. Worked fine for a while, but a couple weeks later my wife smelled a burnt odor, and shortly after, the driver seat wouldn't come on with the remote start. After it was repaired at the installer, who said a diode had fried, the seats go off when the truck is put in gear after a remote start. Not a problem, just different than how it was wired in the first place. They obviously found a better method to do it, but I have no ideas of the details.
So Rngrs3910, these guys had this unit apart twice after the initial install, with no extra cost to me. Any trouble in the future will be handled the same way. Honestly, they didn't make that much of a profit when you figure in all the extra work.