BMW E30 and M30 engines

the M30 engine may be the best engine to Swap in the E30 because you will increase the swap cost if you go for S38-S50-S52-S54-M50 engines and you can have more power than thos engine from the M30 if you got the right modifications on the M30 ,The M30 was one of BMW's best engine for about 20 years, from 1973 to 1993, and It was the original engine for such successful engines as the M88 engine, which was in the BMW M1, and the S38 engine, which was in the BMW M5 and BMW M6. Alpina used the M30 engine with some performance modifications in the E30 Alpina B6

BMW E30 Alpina B6
BHP 260 @ 6,000 rpm
0-30 mph 2.1 S
0-60 mph 6.0 S
0-90 mph 12.2 S
0-100 mph 15.8 S
1/4 mile 14.4 S
top speed 152 MPH

best M30 sources

BMW 7-series
E23
733i 1977-1984
735i 1984-1986
E32
735i 1986-1992
735iL 1988-1992

BMW 6-series
E24
633CSi 1977-1984
635CSi 1984-1989

BMW 5-series
E28
533i 1982-1984
535i 1984-1987
E34
535i 1988-1993