Here is my experience and what I did to overcome the worst nightmares of starter removal. DO NOT USE IMPACT WRENCHES FOR THIS JOB! If you need torque, use long breaker bar , if you need more torque, use pipe on end of long breaker bar. If you have stuck bolts like I did, doing the job on the ground is not conducive to applying a lot of torque on your breaker bars. Oh...it helps if it is your wife's car...she assisted with this job and paid for her own parts!! What a country!
On a lift, you can really apply your body strength to the tools.
Also, don't even think about removing the starter until you have eliminated :
LOOSE CABLES AT STARTER and each and every wire ring terminal in the circuit. Corroded ring terminals, defective neutral safety starter switch.
Make a jumper to jump 12+ volts to the correct starter solenoid energizing wire. ON my car it is the white wire. This is the wire that goes to the back of the solenoid and is a small ring terminal with a small phillips head screw. If you jump 12+ volts to this terminal directly (or to where it terminates on the fender) and still no click or reaction from the solenoid or the starter, then and only then replace the starter. The extra effort is well worth not having to to this PITA job.
First of all, this is not a hard job. It only gets hard if you have seized starter attachment screws..especially the top one which is difficult but not impossible to get to. If you strip one or both of these screws the job gets even more difficult, but not impossible. 5 cylinder Turbos leave you very little room. My 240D 4-Speed has lots of room under there.
Process: A few days before I de-greased that area of engine and transmission housing. Less grease and dripping crap in you face and on your arms..takes 10 minutes. To remove starter: Removed battery negative cable. disconnected starter motor harness from terminal block on passenger wheel housing. Turned steering wheel left to stop. Jacked up car on right side, blocked under wheel,under chassis in two places, blocked 3 wheels front and rear.
Removed passenger side end of the steering stabilizer. Loosened the lower 10mm 8.8 cap screw with aid of PB blaster. Normal amount of rust and seizing.
Top cap screw rusted in place so I needed to put BP blaster or liquid wrench around the bolt to get it in where it is needed. Takes 2 minutes to drill three small holes along the bolt, which only can be done from above for this top starter bolt.
Takes a few minutes to do the following: Removed battery, battery tray, exhaust heat shield, air cleaner housing. Going in from above with 12" long jobbers drill. Drilled 1/8" hole x2 in the bell housing until it hit the stuck bolt. Did one more hole in the ear of the starter motor which is where the threaded end of the stuck bolt was. Added PB blaster, added a little heat.
Tried again: Not even a creak or budge! The universal joint makes things worse.
Since the bolt just declared nuclear war on me there was only one solution.
Go in straight by drilling a 1 1/2" access hole in the passenger footwell. (see photo) Remember: the object is to remove the seized bolt and not to preserve the stupid design of the car! This takes less than 5 minutes and will save you many gray hairs and stripped out screws. BE CAREFUL drilling. I used a 1/8" drill to approximate the location of the desired hole. There is a plastic shield between the body and the transmission and its filler tube. Once you find the right spot which leads directly into the socket of the screw, then use the hole saw attachment on your drill motor. Go carefully since you don't want to drill into the filler tube. The plastic shield will not cut through on the first pass. You have to put the drill bit back through the hole and just lightly touch the plastic shield to make the hole in it. Even if you are slightly off center, this is 100% better than the standard way to attack the screw.
With a straight shot at the top cap screw no luck. More torque, then VOILA@! stripped 10mm screw! (See photo) Time for BOo Hoo, coffee, regroup.
Made a manly easy out (see photo) from my fathers aviation easy out hammered into a 12 pt 1/2" deep socket 1/2"drive. This managed to do the job after trying 10 minutes.
With stuck bolts you just have to keep on trying. Time is not important anymore since you still have to remove the starter screws. The starters weigh approx 27 lbs, so be careful not to let it down on your face!
I used a $2.59 NAPA HEX HEAD 8.8 screw for the top position. Everything went back together easily. USE LOTS OF ANTISIEZE compound. I used antioxidizer on the ring terminals. Plug the hole with either a chassis plug from NAPA or auto finisher supply store, use duct tape, or use a metal plate + sealer and pop rivets.Any of these is easy to remove next time. Put the carpet back and your are done.
Per the recommendation of others on this forum, I bought a BOSCH reman. The $72 core return shipping charge from NY to Arizona was approx $33 on FED EX and is insured for $100. Better than USPS.
When reinstalling, it helps to have someone guide the harness up through the engine compartment while your are getting a hernia pushing the starter up into place. Other than that it is a piece of cake!