My answer: commencing the 3rd year out, merge ST into SP using the SP rules as is, except as follows:
1. Use street tires as ST currently defines them; I'd shop the manufacturers with the widest size selections and try to make it a spec tire class with volume discounts. (prevents testing $$ requirements); either that or fund a club tire test every year with most of the major tires, tested on at least 3 representative platforms. I'd also consider marking one set of tires for every national event and that is the only set you get to run at that event. Maybe 5 tires total to account for flats or other problems.
2. Claimer shocks - $1000 buys the winner's shocks at any national event.
3. full diameter/disc clutche/fw - you could even set a minimum weight
4. ac removal requires front ballast, say 30 lbs
5. non emissions legal/inspection sticker adds ballast, say 50 lbs
6. I'd consider ballast or minimum weights for race seats too, perhaps the ST rule is the right way to go.
7. any non stock aero gets significant penalties; some ideas for penalties would include 1) requiring 10% of total vehicle weight as ballast, 2) set criteria such that no significant downforce is produced, 3) significantly limit tire sizes for cars with non stock aero.
8. I'd consider allowing off the shelf aftermarket cams/heads/stroker components, at least for some classes where such mods are popular and readily available.
Many cars now can overwork a set of street tires as is, even without those components, so allowing them may improve the class attractiveness to the track day/street race/car magazine crowd that feeds our sport, without really upsetting the apple cart.
9. put a roller in grid every car has to get over in order to run, confirming a semi streetable minimum ride height.
10. Screen the class placements to prevent the tiny/large car pairings or other obvious mismatches, and promote popular platforms (vettes/miata/muscle car/bmw/porsche etc.).
I can honestly say that any of these proposed changes, minus the clutch change would run me out of SP.... Just adding my two cents. I think those ideas are ridiculous. Running R-Comps is one of the main reasons that I stay in SP. Not having to worry about internal engine modifications, which keeps my wallet a little fatter is another reason that I stay in SP. A 50lb ballast penalty for not running a catalytic converter is ludicrous. A 30lb ballast penalty for removing the A/C would pretty much negate the weight savings gained by removing it to begin with. Claimer shocks would be pointless, as stated previously. Why would I want to know what the parameters of a CRX shock is? It will not help me. For that matter, why would I want to know what the parameters of Marshalls, or Jeremys shocks are? They don't drive my car, so it will not help. me. I am not a regular Tour or Nationals attendee because I am not at that level yet, but I am a regular at regional events for several years and considering changes of this magnitude would kill the class.. At least for me....