I now how two sets. One square and one with 10.5 et 22 rear. Here is the square set I've been using at the track - 9.5 x 18 et 28. Have not mounted tires on the staggered setup yet. Considering R888 295/30/18 for the rear with 275/35/18 for the front.
2015 f80 M3, 2016 GT3