I want to add keyless entry to my LS trailblazer. I am wanting to know if anyone has taken the system from a LT model and installed it in the LS? Or am i better off just going aftermarket, in which case what are reliable brands?

Hello everyone, this is my first post on here. I tried searching for this on this site, and google. I am getting an aftermarket alarm because my Envoy didn't come with one (I tested it by rolling down the driver's window, getting out, locking with the FOB and waiting a minute. I reached in...