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I have that tire running on my performance on a 19x8.5 set of forged wheels in 240/35/R19 size.
Excellent tire. Extremely comfortable too...it's about as quiet as the pirelli summer tires and very close in grip, if not more.
As to your question - the diameter of the wheel+tire with 245/35/R20 will be bigger. This will impact your speedometer, acceleration, and miles driven - all will read slightly lower by 1.01%. You will have no issues fitting the 245/35/R20 with the uberturbine wheels as they are already 9.0 inches wide (standard for 245).