i WISH it was the M5 engine!!
The M/S50 is the 2.5/3.0L inline six engine that bmw made from 92-95 (94-95 for the M), and it is virtually undestructable, obviously you get the odd engine made on a monday, and you get nothing but problems but it seems most M50 engines were made in the middle of the week, like WEDNESDAY, when the workers are actually paying attention to their job!
My car is pushing 250km's+ and its a WEDNESDAY engine for sure!
No problems with the engine yet (knock on wood) and i track the car and everything!
Theres also are some variations, the 92 2.5L had NO VANOS (aka, GERMAN VTEC) and 93-95 did, same power, i think, but sounds sooooo much nicer!
The 92's are more rev happy, and are capable of reving higher due to the dual valve springs that came with the engine!
ANYONE: feel free to correct me if i fakd up on anything!