Here's the spreadsheet that compiles the big brake upgrade. On the 35d we go from 348x30mm single caliper front brakes to 365x36mm 2-pot calipers. in the rear 320x20mm to 345x24mm. A pretty significant increase in brake capability. Basically the net of it is, a variety of X5/X6 vehicles have the same hub carriers, including the V8 models with bigger brakes front and rear. Fronts were actually cheapest with Cardone BMW rebuilds (ATE/BMW stamp). Rears didn't exist rebuilt, so eBay purchase and a little clean up.