Get a viper and add smart start with gps. U only need the cheapest one way viper, since the phone will get feedback from smartstart, don’t pay for a 2 way and don’t have them run the remote antenna up the windshield. Have them run a circuit for the trunk and wire the side mirror heater (and steering wheel heater) circuit too if they can. You will need multiple bypasses, don’t freak out if they upcharge u for them, but make sure you ask upfront if their price includes them. And yeah u need a spare key, but when you take it out when ur done with the car u get the key back. Any ‘car stereo’ place will do it, they mostly all do viper. I use dragonmaster in Brooklyn but ur closest should be fine. While ur at it look into getting a front and rear dashcams hardwired (I use the b1w with 128gb cards at 720p and a power master pro to keep the front one on 24 hours). I have small kids so I’m having them install rovik running boards and a headrest mounted ehd101 tv when I get the car.