Is there anything i should be aware of before i buy a remote starter.?

If your car is a manual it might not work. But I have had 3 remote starts on 3 different cars and they all were automatics. 20/15/10 is run time as in when you press the on that is how long the engine will stay running until you get in and turn the key. THey are trasferable to other cars. Best gadget i've ever gotten. No more cold car in the winter time.