I was looking over this thread and think there may be some confusion about the need for wheel spacers.
You can run up to 285 width on factory wheels. I have seen 285/75/16 tires on many 4x4 Sprinters.
I have seen 305s on Method wheels without a spacer. Very tight clearance.
Wheel spacers are needed when installing the Agile RIP kit. A coil is placed around the strut. The wheel/tire must be spaced away from the coil for everything to clear.
Wheel spacers are needed if you plan to run a 315 width tire with a VC lift kit. All aftermarket wheels do not seem to have enough clearance. We have tested a 315/70/17 on a Method, the tire just kissed the strut. A 14mm spacer gave about 12mm of clearance. If you plan to lift and go with a smaller tire there is no need for a spacer.
We like the Method wheel width and offset with a 14mm spacer for 315s. The set up allows the slider door to open all the way without interference.
We can also get custom made 17 x 8.5" wide Trail Ready wheels for you Sprinter (same mfg Roam Built uses). I would order with 5.5" back spacing for a 315. BUT there is a possibility of tire/slider door clearance on a 144" with this setup. No spacer would be needed at this point. The wheels start at $460 each and true beadlocks can be ordered. We might order a set for our test van to confirm slider door and tire clearance.
Here is a link to look at wheel width and offset. Great source to compare different wheel options.
Wheel Offset Calculator | 1010Tires.com Discount Online Tire and Wheel Store
Pictures of a Van Compass 2" lifted 4x4 on 315/70/17 because everyone like pictures.