I sell them for dealers. I use DEI product and usually sell the Automate line. Yes, it is tricky on the TB's because of the computer that operates everything. I have to use a special interface that ties right into the computer. That way I can do driver's door unlock 1st, then the rest on the second push. DEI made Gm style keyless units. They are listed as VSE1000 among others. Here's a site that selling some
http://www.oemradios.com/gmkeyenalsys.html
BTW, I sell it installed for under $189.