Thanks for the excellent and most complete DIY. You convinced me to do this on my own. I did not have the bushing puller tool to do this, but I manage to salvage parts at the local hardware store, and biuld a mock up tool.
It was a P-I-T-A puliing the old bushings out. I broke and stripped countless number of washers bolts and threaded rods. Thank god I was using an electric impact gun, because extreme forces are required to remove the old bushings out and insert the new.
Do you yourself a favor, and buy 5/8" threaded rods. Any smaller will strip or break with the tremendous pressure required to remove the bushings.
Also keep lubricating your threaded rods with spray lube. Ditto for the four subframe sleeves, and bushings. Heating the bushing sleeves with a torch did not help much.
Assuming you are not remoiving the subframe from the car, I recommend you loosen up the four main bushing bolts, to help you maneuver the subframe at the rear center point with one jack, and raise and lower one of the four corners you are working on with the other jack. You will need two quality jacks, as you will have to continuously re-adjust to gain enough space between frame of car, and subframe.
Also the rear brake lines need to be disconnected. Get yourself a bottle or two of your favorite brake fluid + pressure bleeder before starting, as you will want to bleed your lines after opening the brake lines.
Job took me about 12 hours, and three trips to the hardware store. What a bitch of a job. Now I understand why the shops wanted $800-$1000 for this.
Took the car to the track tonight with the new M3 bushing installed. Nice difference in the curves and especially through the esses, where weight is shifted rapidly from side to side. Floating and vague movement is greatly reduced. The car behaves much better over bumps when taking high speed turns.
On the street, it makes my 135i back end firmer, and more planted.
Overall, this is a great mod, and this DIY is worth the sweating and cursing...
