I have wheel vibration problem since I got my 2005 E500 4-matic (1.5 years ago)

Original MB rims were bent so I bought new MSW rims from TireRack. Still vibrating but I suspected it's worn tires. Then with brand new winter tires it was ok.

In the meantime I bought new all season Pirellis and aluminum center rings (73-66mm) but they were too small to be put on the car (fits nice on the rim) so my mechanic used plastic ones that are littlle bit bigger on the wheel and he padded it under it with some tape to make it snug. After that it's little bit better but still vibrates.

I called TireRack and talked to Damon, he said that the size is to small and he'll send me right size (73-66.54mm) which he did but they are plastic not aluminum. I called again and was told that thY size doesn't come in aluminum.

So here I am debating is it worth it taking my wheels off and putting the plastic center rings. Of course there is always a chance that this is not the right size either. I would prefer to put aluminum ones and to be sure about the size.
Everytime it costs money to take the wheels off.

Also is it worth going to mb dealership for their "road force balancing"?

Thanks for the input.