first off how many miles do you have on your car?

when your car is cold take both battery terminals off and then put them back on. this will reset your ECU. then start the car and let it run for about 7-8 minutes.

then go do some mild 1x2x3 gear shifts. then do a full throttle 1x2x3 run. maxing out at 70-80 mph.

do this and see if there is still some power loss.