This is a fairly objective comparison 
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I struck a compromise by mounting the stock tire size to new 6” wide wheels. This is a pic of 185HR15 Vreds mounted to an original 5” wheel on the left and to a 6” wheel on the right:
and a closeup:
The wider wheel splays out the sidewall a bit, which stiffens it and marginally improves handling, but the aesthetic improvement is the larger payoff, imo.