You can definitely go 245/275 on the oem wheels without issue.I want to possibly do the same, but I think I got lost in all the different setups, LOL! I guess what I am looking for is the best setup, on OEM 19" wheels, if I am looking to go a bit wider AND not be an issue for a tire shop. I think I am hearing 245/40 front, 275/35 rear is that setup. Is that correct?