What model do you have , the bored out throttle bodies will require a tune to the ECM if your car is an auto , they’re a straight forward change e over for both , Mace Engineering, who are sponsors here have them , check out their website, fitting instructions are available too
I fitted a V8 TB to my engine. It made a definite difference to light throttle but floor it and I am not sure it has made a difference from stock or not. I'd have to swap them over and do an immediate test to see what difference it makes. I certainly won't be going back to a 60mm TB. I'd be interested to test a 70mm but I won't be spending the coin, I will put the $250 towards a diff rebuild with shorter gears.