believe it or not, the stock hpi am radio isn't half bad. i've been running my BL matrix with it for a week now. the range isn't incredible, but other then that, all is well. i have seen plenty of people run the stock radio on the flux with no issues.
They say a good mechanic only needs 2 tools - WD40 & Duct tape. If it moves, and its not supposed to, duct tape. If it doesn't move, and its supposed to, WD40.
Mine didn't work worth a hoot....but....first run I slid it on its lid for about 100 feet, and some of the ensuing damage was to the antenna. But like you, I had a DX3, and that was my first mod to it!
Losi 8T 1.0, Savage Flux - XL style, LST XXL, Muggy, 3.3 E-Revo Conversion and sitting outside 425hp, 831 Tq Dodge Ram Turbo Diesel. It SMOKES
Mine worked, but not very well, it glitched all the time, especially during heavy throttle runs and my Flux would "hiccup" randomly. Running a DX2.0 now and no more issues.