I upgraded from the stage 2 to the stage 3 about a year ago i guess and it really is a significant difference. Car feels more 'open', smoother.. worth it imho. If you have the money, it's def worth the upgrade. Do it.
.
Not sure why ben14142001 wouldn't spend the extra 550 to make his car a true stage 3 after having spent 5 grand on getting it so close.