My 355 has gone from a Performer, to a Performer RPM, and now to an AirGap. The seat of the pants feel, Perf to Perf RPM, was noticeable. I don't expect as much diff with the Perf RPM to AG. Any of the comparisons, I've seen, of Perf RPM to AG were only a couple of HP. I'm not sure you would feel it. I guess if you had a dyno, you would be able to do the comparisons, and be sure of your choice.