I once put in a remote starter in a Mercury Topaz. It took me all day but worked fine.

One of the trickiest parts was identifying which wire needed to be connected to where. An accurate wiring diagram would be very helpful ... a volt meter and continuity tester are essential. I also made notes for future reference identifying which wires I connected, by color code.

I soldered all connections to ensure that I had the best connections; however, as an alternative, there are plastic splicing devices available that allow you to connect to wires without cutting ... just clamp the device onto the existing wire along with the added wire you want to connect.

Also, rather than cut existing wires, I very carefully stripped-away some of the insulation with a wire cutter and utility knife and then soldered the remote starter wires to the existing wires and taped all exposed wiring with electrical tape

Allow yourself plenty of time!!! Good Luck!!!