I'm on the luddite/curmudgeon side of things on this one. Had a viper alarm & key-fob for the locks. Didn't care for it. On Blackjack, I can't get the crappy LMR actuators to work worth a damn. I'm guessing I need to clean & lube everything connected to them, and/or maybe find better ones. But, despite the fact that it's my daily & I do lock it in some places, I am otherwise in no way interested in remote start, keyless entry, or any of that. To each their own, though.
The factory rke system used through the 90's is easy to adapt to our cars and plentiful in wrecking yards. I have the system in my 88 truck with the keypad.
All you need is the rke module, harness for it, key fobs and schematics for your car and the car the module came from. Look for these in 89- 95 Taurus, 92-96 f150, 94-98 mustang.
Really anything from about 90-98.
I have done it in my truck and I'll do it in my 89 gt. I'll do a write up when i get to that point.