I believe if you go with a concave wheel you will be fine. My only concern will be brake and strut clearance. It may fit without hitting the strut but will be close. A comfortable offset for a 9" wheel is between 10 and 25 for the Magnum. Going with a 45mm offset will move the wheels closer to the strut tower. If those are wheels you must have, consider getting a set of 1/2" spacers (at minimum) to go with them. RTs don't have the Brembo package so you can get the same size spacers for the front and rear without issue. Hopefully this helps.