I used the stock BMW rubber grommet and cut the hole to match that. I did buy a new one though as the one from the doner was starting to fall to bits!
I'd buy a new BMW one then cut the hole to match it
realoem.com is down at the moment. I'll dig a part number out later.
You using the donor gear stick? If you want to shorten it up a little buy a stick from a 1.9ltr Z3 takes the row boat action out of E30 boxes! Only £30 or from a main dealer!
Here's a comparison piccy:
http://www.msportster.co.uk/faq.asp?FAQ=2
I've got the 3.0 Z4 one for our Sportster - very short shift!