Lange won't mention names, but he will mention that several well-known Pro Stock racers have used the two-stage valve. And recently, on a well-sorted-out bracket car, quarter-mile runs dropped from slower than 10.61 @ 120 mph all the way down to 10.31 @ 129 mph as the carb was tuned to work with the fuel regulator.
More recently, the Vrbancics used Lange's regulator on a 555ci Rat, sporting, among other things, one of Vrbancic's own 1150-cfm Dominators (which George Vrbancic says actually moves 1280 cfm). Without the regulator, the big-block put out 787 lb-ft of torque and 972 hp; with the regulator (set at 2.8 psi low side and 8.5 high side) and the Lange-supplied .150 needle valves installed instead of the .120s, power bumped up to 793 on the torque and 979 hp. Time didn't permit fine-tuning (i.e., going to leaner jets), but George Vrbancic assures us that given the time, and all that unaerated fuel getting to the carbs, the power gains would be even greater.
Granted, this evidence is anecdotal. Like we said, however, it also sounds very promising. Dave Lange, however, accomplished his main goal, which was to create a regulator that allows drivers and tuners to control a problem. "This is the most controllable (regulator)," he says, "'cause you're controlling all aspects of fuel delivery to the carb, from dead idle to wide-open throttle. It does what it's being told to do." Sounds like the best of both worlds to us.