Since techpool has a huge impact on price, and price is 3-star for category S, I’d vote for much stricter techpool rules at least for that category. (Quality rules are fine IMO)
Since this is Letara, how about taking the LHC3 techpool rules, adding a few selected points here and there (similar to the evolution from LHC2 to LHC3) and making that techpool mandatory for category S at least?
Perhaps also for R and X, with a few (R) and a couple (X) TP points for everyone to distribute freely for a few selected unlocks or stat boosts? (For category S any points to choose will end up in chassis, engine family, fuel system or interior anyway if price stays 3-star…) Max price may need a slight adjustment in this case for all three categories (or even not?).
See also