All above very good info.
I've had my trans out several times, here's a few more tips that I found worked well for me -
First, when I reinstalled it the last time I used blue loctite on the swingarm pivots instead
of red. Marked them so I could see if they ever worked loose. They had not. That saved
quite a bit of time heating to loosen red loctite. Of course, on that one all the "normal disclaimers" apply.
I removed the fuel lines, press regulator & injectors after removing the airbox instead of before.It was much easier to remove after the airbox is out and I felt there was much less chance of damage to the lines rather than trying to wriggle and pull them out while the airbox was still in place as the manual directed. I just popped them out of the slots in the front of the airbox so I could pull the airbox out first.
I cut the shift indicator wire and installed quick disconnects in the wire behind the starter instead of
threading that long wire all the way underneath and thru that mess under the ABS brakes to
reinstall the shift indicator switch and reconnect it. Why doesn't the shift indicator switch
just fit thru the hole in the trans case? That was a major aggravation and was time consuming
the first time.
I removed the 02 sensor and left the wiring connected instead of pulling the wire out and then having to rethread it behind lots of stuff all the way up to the connector in the under-tank area to reinstall it.
My manual said to also disconnect the throttle cables from the throttle bodies. I didn't do that, just
was careful as I raised the back upper frame. The cable outer sheath pulled out of the TB adjusters but no
damage or problem. Just made sure they slipped back into the adjusters when I reassembled. Saved
a bunch of hassle and re-synch'ing the TB's.
Not hurrying at all, and taking three 10 minute breaks, I had it out in under 3 hours.
That was a far cry from - well, I won't even admit how long it took me the first time.
Of course that was following my oem shop manual step by step, referring to it frequently
as well as the online parts fiche to find some of the things the manual talked about. That
was a big help the first time thru as the CD manual I had (got it off ebay quite reasonable
and it was pretty complete for the most part) didn't show some of the little parts or called
them different names so I was able to look in the online parts fiche to find them.
Here's a little gadget that I made up for a clutch alignment tool. I'm a packrat and save all manner
of little goodies. Once in awhile it pays off!
http://s719.photobucket.com/albums/ww20 ... nt%20tool/
Don't even think about ordering a commercial clutch alignment tool aftermarket. I tried and never got it. Unless you shell out the big bucks for the BMW tool.
You can avoid the hassle altogether if you scribe a mark closely around the disc (where you can
access it) before you take the clutch assy apart. Or spray a little dab of spray paint at the edges
of the disc - anything to show where the original sat before you take the clutch apart. When you
put the new clutch in, just align it to the scribe marks or spray paint. Install the bolts JUST tight
enuf to hold everything in place, then lube the trans input splines and carefully wriggle the trans
into place. Another thing that helps the input shaft to clutch alignment is to shift the trans into
6th gear and fasten a vise grips, etc, softened by a rag or something, to the trans output shaft.
That way you can rotate the input shaft bck and forth by rotating the output shaft. That often
helps get the splines lined up even tho the disc is centered OK. Then carefully pull the trans STRAIGHT back so you don't disturb the clutch disc. With the trans removed again, finish installing & tightening the
clutch bolts. You gotta use new bolts, they're "torque to yield" so are only good for one tightening. At least they're not expensive.
Another thing on the clutch - each of the 3 main pieces have a "color mark" on them from the factory. they can be a little hard to find under the dust and dirt. Find them BEFORE you take the clutch apart.
They're supposed to be about 120 degrees apart, or 1/3rd of the way around. You might want to make
some fresh marks with a paint stick or something, matching the pieces together. You have to put them
back together like they come apart so things are properly balanced and don't vibrate.
The first time I pulled the final drive and driveshaft an all that stuff apart. I pulled the tube off the FD
so I could lube the FD input splines, was kind of fun getting that bck togehter. Should be reassembled
so the U joints are phased. I got the rear half of the shaft attached to the FD, then attached the tube
temporarily (later torqued the pivots). Then stood that asembly with the tube open to the top, and using a flashlight got the U joints aligned between the front & rear half of the shafts. Just took a little patience
and a couple tries for the splines to slide together.
Maybe an easier option (I later found out lubing those FD input splines may not be necessary) is to take
the entire tube & FD assembly out together. The only problem then is getting the drive shaft snapped
back onto the trans output shaft. You have to work from underneath which is a pain if you don't have
a lift (I made myself a lift I use with my floor jack after doing the trans thing the first time). I used a big
screwdriver (real big long one) that I stuck in the front U joint after I got everything positioned / hung in position, then holding the handle of the screwdriver pounded on the screwdriver shaft right up by the U joint which popped the front U joint onto the trrans output shaft over that snap ring. Not easy to get at, but probly easier than all the fiddling if you take the driveshaft & tube all apart off the final drive.
First time thru it can be easy to forget how small vac lines & wires are routed - make notes and tag plugs
and ends of lines to help you remember how it all goes back together. Or even take some closeup pics.
Totally possible to do yourself if you have some basic wrenching experience, and take it slow and easy the first time and study it as it comes apart.
http://s719.photobucket.com/albums/ww20 ... 20Removal/
Good luck!
Afterwards my friend said, "You told us exactly what to do, we just totally failed to do what you said." 
) the gearbox back into place (using it as its own centring tool if you like). Then rather than pull the 'box again and risk things moving, simply do up the pressure plate bolts through the starter motor hole, by rotating the engine to bring each bolt into the starter motor window. (If you put a felt-tip pen mark on each bolt as you do them up then you can make sure you don't miss any).