R888R 315 vs 325 width

[Jasoneo5]

All,

F10 M5 guys are putting R888R 315's on their factory 10" rear wheels, most showing great results. Since our wheels are 10.5" (12.5mm wider), would one see a benefit from going R888R 325/30/20 (instead of 315)?

For comparison, my current 305 SC2's are have a load rating of 103y. 315 R888R's are 101Y, and 325's are 102Y - thus wouldn't the bulge be similar across all 3 widths?