Why would you need a master cyl... It's the same part number. Also.. Front subframe is the same, only difference is the arms and front anti roll bar(1M).
OP, are you using the standard 135i swivel bearing, handbrake setup and rear caliper? 135i twin pot doesn't bolt onto M3 rear hub and doesn't sit in right position on disc. Also, discs pictured aren't m3
any info would be great.