I had 16x8 wheels with 215 rubber on my '84 wagon and it railed! Nothing wrong with the handling on 123 chassis cars. The seats, however.... I fabbed some brackets and put sport seats from a 318is in the car. You'd be surprised what some bigger seat bolsters will do for your car's handling characteristics.

Jay

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On the road, currently:
'83 300D (German spec.) 168k mi. - - Wolfgang (tucked snugly away for the winter!)
'87 300D 375k mi. - finally went over to "The Dark Side"
'87 300TD 225k mi.
Cannondale 66cm CAAD5 w/Campy/Jamis Aurora
Hujsak Custom Fixie/Landshark Track Shark Custom/Ahearne Custom 29'er