So how wide can i go on the stock 18" wheels? Also, whats the width of the F and R wheels?

Thanks.

Fronts 7.5" Rears 8.5" You could probably go up to a 245 on the fronts and 255 on the rears.
IMO, Anything wider and the profile will look funny.

he is right

i went 235/45 up front and 255/45 rear

my snow setup is 245/45 on all 4