I've had my Accufab elbow on for about 2.5 months now and For about the first week I could tell a difference throughout the entire rpm band. Now it's old and I suppose I've grown accustomed to it's new power. I'd reccomend it or any of the new upper elbows. From track times I believe I've gained 2-3 mph. I've heard alot of good about the Accufab elbow. Visit "modulardepot" and read the two write ups on the upper elbow tests. Accufab was the top dog in both tests. But every car responds different. I think a dyno tune with a custom tuned chip would really make any of the elbows shine due to the corrected A/F. Some peoples A/F have been off from the new elbows. Hope that helps.