After much looking, I replaced my '88 Salad Shooters with C6 Speedlines. Love the sculpted facets on the thin spokes, not a fan of the flat "wagonwheel" look of C5 wheels. The 19"R/18"F gives it a slightly more contemporary look in my eyes. I have not seen many other C4's with this set up......I keep telling myself that because they are such nice wheels, C6ers don't replace them.
The Torque Thrust wheels look good. After three years, I am quite used to the C6 wheels and they seem to look decent on the C4, C5 AND C6. I like the 18"-19" look too.
I sold my old thin spokes to a fellow down in Regina. I haven't seen his car yet, but I've seen C4's with them on and they look great! I was actually hesitant to sell them as I really liked how light they were.