Actually... this theoretically COULD affect WOT performance. If you do in fact run too rich at part-throttle becuase of this mod, the ECU will compensate by leaning out the short and long term fuel trims. You may very well end up with a mild lean condition at WOT! Depending on what state of tune your car is in, this could improve (or hurt) performance at WOT, but it would be a crap shoot.
My guess is that the bigger part-throttle gains come from skewing the load calcuations. I would think that more perceived throttle but less air = less load, so maybe you'll end up with more spark advance at part throttle. This is the ONE THING that the ECU can not "learn out," but again, this is part-throttle only. It's easier to just press on the gas harder.
It would be much better to get a chip that reduces tip-in spark retard and replaces stock the A/F and spark maps, but you get what you pay for, I suppose.
