The E30 wasn't even close to the first M-car. The first M-car was the M1... guess what, it had an inline-6. The second M-car was the M535i, which was an I6. Then the M745i which was an I6. Then the M635 CSi, which was also an I6. Then the M5, which guess what, was an I6. Finally we reach the four-banger M3.