Not noticeable. I was more focused on my rpm range rather than top speed. How many times are you going to flat out for more than 1/2 mile without burping the throttle? For what it's worth, on hwy 50 out by sand mountain a buddy of mine and I were on the asphalt going flat out for over a mile. Both had stick tires but I had an alba exhaust and the afr4 dobeck controller along with my rage 6 and I was a good 5-7 mph faster than him. I could walk away from him at any time ?