compustar 2wfm range problem

I recently installed a compustar 2wfm 2 way remote starter/alarm in my 240sx, and my range is awful. I have a strip of 20% tint across the top of my windshield that comes down about 5 or 6 inches, and I mounted the antenna on the tint, top-center of windshield horizontally. Where should I relocate the antenna to get the range that is normal? my previous alarm/remote start was a code-alarm 2 way and I had the antenna mounted in the same place, and my range was way better, so I didn't think it would be an issue to use the same mounting spot. Any help is much appreciated.

Below the tint would be ideal.....If you use good quality film, you would know it has metal in it. This will definatly degrade the signal. Maybe try up along the A pilar.