I think your concerns about wide tires are real. When I bought my car in 84 it had mag wheels with bias plys on it. I put some 60 series 215's on and within a year or two I had the clunk in the steering box. I think the wide tires and heavy wheel assembly accelerated the wear. I bought some stock wheels from GM and put on smaller radials. Car tracks much better even with some slop in the front suspension.