any thoughts , if it were to be made a "legal" thing, what it would to to competition balance ?

I think, for the "worse " motors it would help more (miata 1.6 bp, Honda D series, older 1980's stuff) than the front runner engines like K series honda (and I guess, some miata bp's, hah), but would it just be a bigger hoop to jump to build a "top flight" engine?