most shops will carry and install dei products (viper, python, avital . . .), code alarm, autostart, crimestopper. all good brands with different options and prices. i'm an installer and have done many over the years. A professional install is always recommended since you're messing with the vehicles electronics. Also keep in mind that you will need a bypass module due to the chipped key and that requires you have two keys for the car to program that module (you get both back after the install). If the car is an ATX then it's pretty straight forward; if a MTX then it will require specific mtx compatible models and additional parts. These mtx units have a safe mode to make sure the car can not be remote started while in gear.
Push button start is even easier to put in. Just need a desired button and a bit of wiring knowledge.
I have remote start/keyless/security on my focus as well as a custom ignition setup with push button start and love it. Lots involved in it, but well worth it.
2010 Volvo C70
2011 Harley FLHTK
Midwest Crew #22