As I understand it these will plug directly into the port under the dash and work without installing under the hood? this is on a 02 dmax, and if it works this way, does it leave a foot print in the computer?
Yes, that is correct as long as you get the Evolution CS or Evolution CTS. The Juice/Attitude CS and CTS plug in underneath the hood. If Gm wants to find out you have had something to enhance the performance on your truck, they can. However, as long as you dont give them a reason, most are very cool about mods.