I am getting a spoon rims pretty soon
and the specs are

16x7 +35 fronts or 16x7 +45 (for non Spoon caliper fitment)
16x8 +45 rears

what's the best size tire I can put on?
for daily driving and little tracking from time to time.

thanks in advance.

 

I would stay with 205/55R16 and 225/50R16. Anything wider and you could have problems. If I can help with the tires let me know.