My 2011 GT has a strange issue. With a cutom tune from vendor "A", my car runs better than the other tune I have purchased from another reputable vendor. The issue happens when the car downshifts from 2nd into 1st as you come to a stop. Every say 5th or 6th time, I get this clunk that feels like slop it the driveshaft. It only happens with the one tune. Of course that tune is my favorite as it seems to hold the revs a bit longer during normal driving and the car just feels stronger. I had the vendor try to adjust it, but it still happens. I guess my long-winded question is, WHY DOES THIS HAPPEN with this tune, and do you think it will hurt my trans or driveshaft components in the long term? Thanks guys!!!!