17s look great, i was of the same mind but took the chance and was pleasantly surprised. with the lower tire with stiffer sidewalls the ride is a tad more sensitive to bumps but improved on corners.

I will go to the 275 40 17 next year mabey or year after ,but I think the 225 50 16 is ok ,these base cars orginal was 215 60 16 wich have to be tall ,now yes on the z or ss 245 was stock

I'm thinking about 18" wheels vice changing to 17" wheels. Any real negatives there, other than the harshness of the ride over rough roads?

limits the width you can go both front and back. it would require a lower stance tire which would effect ride.

Looking at it, I'll stay with replacing my 16" stockers with some 17" ones. I've found this site which makes reproductions, and they seem somewhat legitimate.
If I go through them, these C6 wheels looks spiffy enough. Not quite the SS wheels I would prefer, but they're close enough while being cheaper.

ya 17s seem the best an the price for 18s goes way up so 16 an 17 ,its like I went with 225 55 16 on the base same hight as a 235 55 16 ,just 3/4ths in thiner but a 99 w about the 95 index for weight 1700 per tire to the 1500 needed you can go up but now below 95 load index ,I finaly after checking out one of those new tire calculaters the diffrences between the new way an old way with tires