I found the source for this. Here it is if anyone else wants to do this fix: Shift Linkage Rebuild (Torn gearstick boot)
[ Jeff Krause :: 01 Jan 2000 ]
The E30 shift linkage is fairly sturdy, but over time the associated bushings wear, allowing the lever to move more and more before doing anything useful. This slop is particularly noticeable in the side-to-side plane, where the lever can sometimes be so loose it becomes hard to select reverse! But have no fear, not only is this a relatively in-expensive fix, you can firm up the shift feel significantly in the process, making the shift action brand new again.
The shift lever is about a 10 inch long rod of stainless steel, and about 1.5 inches from the bottom is a large ball that sits in a special socket. This in turn rides in a cast aluminum carrier that bolts to the back of the transmission through a rubber bushing, and ends in a rubber bushing just behind the shift lever. As these wear, the whole assembly can rock back and forth, causing the sloppy shift feel. The whole mess is directly above the driveshaft and front guibo joint, which makes it very difficult, dirty, and unpleasant to work on. But trust me, it is worth the effort to change the bushings!
Order the following parts from your local BMW store:
Bush bearing 25 11 1 220 832 $8.76
Trans shift bush 25 11 1 463 397 $11.92
* 6 supt brkt 25 11 1 220 707 $20.34
Spec. circlip 25 11 1 220 379 $0.54
Spec. shim 25 11 1 220 439 $1.14
Bolt 25 11 1 225 344 $6.90
* Optional, but recommended!
If you haven't degreased the underside of your car in a while, now's a good time to hit it again. Raise the car on 4 sturdy jackstands as high as you can get it. Be SURE, by aggressively rocking the car, that it will not fall on you. Once secure, get several cans of foaming degreaser and liberally spray the backside of the transmission, transmission tunnel, driveshaft, and shift linkage. Wait 15 minutes, and thoroughly hose off the underside of the car.
Put the car in neutral, then climb under the car. Looking at the shift lever stub that's visible from under the car, find the retaining clip that holds the lever to the shift rod that runs forward into the transmission. Pull this clip off with a pair of needle-nosed Vice Grips or equivalent.
Remove shift knob by pulling HARD on the knob. You may have to twist slightly to do this. If all else fails, wrap the lever directly below the shift knob with duct tape, and clamp the lever with Vice Grips. Then use a large screwdriver to pry off the shift knob.
Disconnect the reverse-light wiring connector and remove the shift boot and insulation. You can now see a hole several inches across in the transmission tunnel, and below it is a cast aluminum piece that the shifter ball sits in. A white plastic socket holds the shift ball in the aluminum housing.
To get the shift lever out, you must first rotate this plastic socket clockwise about 45 degrees. Take a long screwdriver, and tap at an angle between the teeth to rotate it. (If it breaks, you now know why you ordered a new one. If not, I'd replace it anyway.) When it won't turn any further, you should be able to to yank the lever up out of the housing.
Separate the shifter stub from the horizontal shift rod. Pay close attention to the orientation of the yellow spacer washer as you remove it, as you will want to orient the new one in the same way. Mine had the beveled edge facing out. I then used a long screwdriver to pry the two levers apart. Remove the shift lever.
The aluminum housing that holds the shift lever runs forward to the tail of the transmission. There is a stamped metal bracket that holds the end of this piece to the transmission, and it attaches with 2 13mm bolts. Remove these.
Pull the whole assembly down, forward, and around the passenger side of the driveshaft. The housing tapers to a rod a few mm in diameter in the back, and this pushes through the rear bushing.
It will give enough to slide the whole mess out from under the car. Degrease this, drink a beer, and then move on to step 6.
Once out from under the car, remove the 13mm nut from the bolt that holds the sheetmetal bracket to the front of the aluminum housing, and replace the bushing.
I bought a new bolt since mine was corroded, and I did NOT want to have to go through this again! The darn bolt was nearly $7.00, and is apparently made of BMW's favorite material, "Unobtainium".
But you can't just substitute a normal bolt because if you do, when you tighten the nut it will crush the bracket and bushing, transmitting engine vibration directly into the shift lever. In an E30 M3, it is a LOT of vibration.
Don't ask me how I know.
This is optional, but recommended. The rear support bracket and bushing is what the assembly slides into to support the rear of the aluminum housing. As the rubber gets old, it gets more compliant allowing the whole shift lever to move around.
Only one bolt holds it in the car, but to get to it you have to remove the heat shielding above the driveshaft. I undid the first couple of bolts, and pulled the heat shield down enough to get my hand inside with a socket wrench. Replace with the new piece, and reinstall the heatshield.
Put the whole mess back under the car, slide the tail of the shifter housing into the new bushing, and install the two 13mm bolts that hold the front bracket to the transmission.
Remove the old white shift-ball socket and discard. Replace with the new one, drop the shift lever down into the socket, and rotate it to lock into place.
From under the car, connect the shifter stub to the shift rod. This can be difficult, so be patient.
Be sure you have the yellow washer in place again.
Replace the shift boot, insulation, and re-connect the reverse light wiring. Snap on the shift lever, and you are ready to go!
This information is from http://www.bmwe30.net/cgi-bin/datacgi/data...0099&Section=11