I know of a N54 complete swap with 6-speed
320i (1992) M50B20
320i (1992-1998) M52B20
323is (1995-1999) M52B25
325is (1992-1995) M50B25
328i (1995-1998) M52B28
328is (1995-1999) M52B28
M3 (1992-1995) S50320i M52TUB20
320i/Ci M52B22/M54B22
323i/Ci M52TUB25
325i/xi/Ci/ti M54B25
328i/Ci M52TUB28
330i/xi/Ci M54B30
M3 S54B32
M3 CSL