I think 3.55's would be great with a SC I had 3.08's stock and had gone with 3.55's before I installed the KB thinking they would be too much but then found myself wishing I had left the 3.55's in there. Last summer I installed a Z-spec world class tranny and was going to order another set of 3.55's but they talked me into 3.73's since my first and fifth gears were taller than stock... I have to admit that I LOVE my 3.73's!!! Of course my car pretty heavy and with me the full stereo and a tank of gas it is aproaching 3700 pounds... But I would say that 3.55's would probably still be a good choice. Good luck with whatever you decide!
------------------
92GT all the free stuff and a few bolt-ons, lowered with Ebiach's and Koni's, Kenny Brown subframe connectors, lower G-brace and jacking rails. BBK upper and lower control arms, polyurethane bushings all around and Ken Bell blower, ram-air, 80mm mass air, etc.