First - assuming you're running regional events - do what Loren says and just run. You can be technically illegal and it's not a big deal in the local seen as what you're talking about doing is converting your car to an M slowly over time. That'll be understood. Worst case is that someone throws a hissy fit over a $3 trophy and you move to CSP or STS2 - big deal. I don't think I've heard of a protest at a CFR event since I started running with them a year and a half ago.
Next - Springs don't wear. They do sag but their rate doesn't change over time. You don't mention a sway bar. that'd be your first mod. You can run any front bar in stock and if you're converting to the 94 M specs, you can run the 94 M bar in the rear. Shocks wear and can be replaced with (almost) any other shock in stock. I've hear good things about the Tokico's from a cost/performance standpoint. Koni's are great. You also don't mention bushings. They DO wear. I'd think about replacing those. If cost is a huge issue, I'd use new bushings but you might find some deals on used sway bars, shocks, and 94 M springs.
Personally, I think you're better off running in STS2 on street tires than CS (or ES) on street tires.