do u have a check engine light
if so does it come on
they do feel abit doggy off the mark if the o2 sensor isnt fitted or powered up properly
also does the vvt cut in
also like pornstr said the 6 spds make it feel like a new car but would cost abit
or u could try changing gears at 7800 or 8000 rpm and see if it feels good if u dont already do that
also does it rev past 8000 as a low percentage have a 7500 or so rev limit if the ecu doesnt have a spd signal
and last thing is pull cover off ecu and check inside for leaking capacitors