I replaced the old one which was shot about 20 months ago and the thing is shot again. I dont know why, but nevertheless, I need to reapair it again.

Why are these things plastic when it is located right next to the hot exhaust manifold?? Are there any tougher ones out there, ie, spherical bearing, etc..?

Why would this thing wear out so fast?

Check the steering shock.
That helps dampen the force on the idler arm.

Balance, balances all
 

Brother of The Benz, herr leber
Vibrating front tires from improper balancing will destroy your idler arm bushing and all other components in the front suspension.
Too often the steering stabilizer shock hides these vibs that are damaging the front suspension components.
Replace the rascal again and have the front suspension inspected for loose(warn) items.
Happy Trails beep Beep from The Spiderman in Houston!!!

Thanks Spiderman, you have a point. Right after I put the new idler arm bushing kit in, I drove on a long trip (NY to S, Carolina) with two brand new front tires , balanced of course. I didnt even get home from Sears the dya before the trip(sears mounted the rubber) and I lost the wheel balance weights. Nevertheless, I drove to SC with the heavy vibrations from both front wheels- like 14-16 hours each way. You know how the Benz rims dont take just any bang on lead weights due to the lip.

Here I go again! New bushings and dampner will be on the way.

I experienced frequent replacement on my 201 as well. Make sure that whoever installs the new ones uses the correct torque when installing. The temptation for many shops is to overtorque, which greatly reduces lifespan. I had one shop look the correct torque up, then declare "that can't be right" and procede to crank the you-know-what out of it.

Try using the 16V lower bushing as it's much heavier duty!
Part number for the kit is 201-330-01-75!

To Get It Smooth
 

Brother of The Benz, Herr Leber
Benz light alloy wheels can be a bear to balance properly.
Most balancer operators fixture the wheel with a flat tool on the inside and a cone in the small cap hole or a rubber multi-fingered tool on the outside of the wheel.
This technique will NOT align the wheel on an accurate center line.
DEMAND that cone tooling be used at both the inside and outside centers of the wheel.
In doing this you will have the BEST balanced wheel/tire you've ever had.
DEMAND that the weights be attached only to the inside of the wheel. Using the clamped and the taped on weights.
Smooooth all the way to max cut off.
I too use Sears NTB, but I've had to try more than one shop to get my balancing performed as "I" want it done.
Happy Trails Beep Beep from The Spiderman in Houston!!!