So I recently picked up a set of rays and was wondering whats the best size and tire to run on these. Searched around the interweb and a bunch of conflicting ideas. Please help me out thanks in advance

I would run 225/45 on the front and 245/40 on the rear.

I could never understand why Nissan thinks it's necessary to run smaller tires in front. You could easily run 245/40X19 on all four corners for a very stable ride, that's what I used on my last Z with total success.
Gary

yea, i'm running 245 40 on all fours

Anyone know how the ride differs with smaller front tires compared to 245 all around

More understeer.

245x40 will work fine, I had 245x35 all around for a while.

i personally would run 245/35 or 40 front and 255/40 rears.