It would've been most interesting to see them use the exact same tires for their upgrades to compare apples to apples. It's a bit more of a PR stunt when you have different manufacturers and different compounds against each other.
Nevertheless, a good indication of the benefits you'd see out of stickier rubber. Would've been fun to see a full R-comp that was shaved and properly warmed up for good measure.
2013 335i M Sport /// Alpine White/Coral Red