I had a DEI Sidewinder installed by Bestbuy only because I know the installer personally and Bestbuy offers a lifetime warranty on the brain module. I got the Sidewinder 6500HF which has Remote start on it and 4 button remote to control my back glass and window rollup.
But any DEI product like Sidewinder or Viper are really good choices.
I've installed all my other alarms on my 91 s-10 pickup, 85 s-10 blazer, Mercury Cougar, 97 s-10 blazer, all Vipers and I didn't have any problem. Took my time, soldered all connections and heat shrinked all wires. Good quality work since I did it myself. If your not that electronically inclined they maybe pay someone else to install it, like the alarm place you purchased it from.
Mav