This is the company that I used. Cost includes shipping your old driveshaft to them and shipping it back to you. Took a little longer on my 760 as it was a special build. However the 750/745 should be covered. In the listing. They also use a company/office in the Los Angeles area so it doesn't have to go to Texas if you're in California.
Rebuilding it could be very expensive if the shop tries to do it with just the parts and did not have the equipment. The universal joint cannot be taken apart without special tools. Other than that, taking the driveshaft out itself is a fairly simple operation. Also be advised that the cost of the replacement also includes a new center carrier bearing.
A forum community dedicated to BMW owners and enthusiasts. Come join the discussion about Bimmerfest events, production numbers, programming, performance, modifications, classifieds, troubleshooting, maintenance, and more! Bringing the BMW community together.