I just sold my x50 on ebay. I have had the sti now for about 3 weeks. I love it. I have the a4 m9 right from beltronics. I have done lots of testing on the sti and x50 side by side. On ka band the sti beats the x50 by about 3-5 secs. Some times the sti will alert a small ka blast nothing from the x50 and then its silent then about 10-15 sec later both the radars start to alert ka. The sti from the side and rear I believe is better than the x50. No overheating problems yet. I had the sti in my car on a very hot day about 94 degrees. I had a temp gage put in the window and it got up to 144 and the sti still worked just fine. Escort tech told me they test them up to 155.