I'm considering getting a big brake kit (6 piston calipers, 304mm rotor) from the company I got my Volvo BBK from, CEIKA. I'm not confident the brakes I have will be sufficient with twice the HP. They make them to fit anything, but it's always easier to not be the guinea pig. They already have a listing for 74-84 Fiat 131 fronts. The question is, is the rotor hub offset and caliper the same as our X1/9? I can't find anything online that helps me figure that out. Any one have any info on the 131 that would help?