hi, i have 17x8 45 and 17x9 40. I was planning on reverse mounting the rims when my tires die on me. I have my fenders rolled. what would my new offset be after reverse mounting the faces? would i need any other modifications besides the fender roll i already have?

 

oh and by the way, would i be able to flip them back or is this a permanent modification?

 

It's not permanent, but you will need quite a bit of camber and pull. From what I've heard, the difference in offset is around 15mm, so that leaves you with the rears being +25, which is really aggressive. For tire sizes, I'm going to guess somewhere around 205 and 235 with somewhere around -4 camber, depending on how low you want to go.