355's would make a big differance in seat of the pants feeling as far as acceleration goes, I don't think it would be wise to go much steaper than that. If you are planning to do the Sean Rowe Super Charger I would keep the stock 3:07's.
I do believe his kit is available already and that he may be taking orders for it.
Pick up some headers, get a 3" exhaust, get rid of the cats and you should be pushing some where around 410 RWHP 480 RWTQ. This is what Lauri's (REDENUFF 93) car put down, with the same set up and nothing more. If you need a guy in the area (lebanon) he can do all your custom exhaust work and pretty cheap to, has done mine and Lauri's car, let me know. The Gen I's are big torque cars!! The stock exhausts on the Gen I's are the big power killers or restrictors.
As for the Gen II, I have been driving the 01 GTS and while it is noticebly quicker than my Gen I was before the total engine build, and heads / cam setup. To me it is just not as much fun!! Give me a call some time you can take it for a spin and see what you think of the Gen II vs your Gen I. The differance is so marginal (50 hp) and can be made up pretty easily. Your 02 Z06 probably would have whooped up on your stock Gen I, same power but more weight in the viper.
Ed