Found this kit from Ultimot. Looks good
With this high-quality set, the BMW X3 and X4 are converted to a high-performance sports brake system. Included are all required parts including the 6-piston fixed calipers, adapters, pads, steel flex brake lines, bolts, screws and all small parts, as well as our powerful, two-piece perforated sports brake discs in 374x36 mm. With the help of these brake discs, the standard bolt circle of 5x120 mm can be reused without restriction. This kit is designed for wheel bearing housings with an eye clearance of 138 mm. An admission can be carried out by individual acceptance. It is possible to ride wheels from 19 inch - please ensure clearance in the rim before purchase.
Installation and acceptance
Diameter:374 mmPCD:5 x 120 mmAvailability:
Wheel width:36 mmBrake discs:Perforated in several partsOn order
Number of pistons:6Color option Saddle:blueREQUESTS
Item number:BK740Businessprice (incl. VAT) 2.666 EUR TO BUY