Since I haven't seen the movie I assume you mean putting a manual transmission in a 750iL. A guy name Gale at
http://www.nmia.com/~dgnrg/page_2.htm converted his 735 to have a manual transmission for around $2500. I would think you would need a more hefty transmission for a 750 but there should be useful information there. Gale seems to be a really nice guy and I'm sure he could give you lots of good advice.