The car came with front and rear BBK with the 6 piston calipers in the front when I bought it from a friend..
I also posted the question on e30 M3 SIG and have Porterfield-Brakes alternative pads coming in a couple days. I's always good to ask a race car guy since they seem to be very resourceful.

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2001 x5 3.0 (sold with broken motor), 1990 e30 M3, 1991 318is, 2002 325i, 2008 335i Dinan stage 3 6 speed,