Throttle body upgrade 80mm or 85mm?

[94CLUBBY]

i,m currently in the process of installing a OTR intake and larger throttle body on my VXR8,i,m thinking 85mm is to big what do you guys think?its already been tunded to 300kw aftermarket headers and big bore no cats,larger maf sensor,i will be still using my maf sensor also.

[Aussiecv8]

why upgrade if you dont need too? especially since its just to suit a new otr. I'd rather save the money.