Bearings VS bushings...
I would assume that replacing the thrust arm "bushings" with "bearings" would cause an enourmous amount of roadnoise and a jarring comfort level to say the least.
If you are only concerned about Tracking the car I'd say go for it, if you plan on driving it I'd say to stick with a bushing. The 750 bushing is stiffer than the standard one and ride quality suffers a small amount but is still very acceptible. The 850 is probably stiffer since it is for an even heavier car.
95 E34 530I V2.37
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