What makes S4 and later gearbox 1st, 2nd and 3rd syncro ring so expensive ($200+) compared to all other types? Price is almost double to same vintage 4th and 5th which is second most expensive version. Can fact that 1-2-3 are made of steel when 4-5 is brass explain difference? Some syncro parts are reputedly same or similar as 911 G50 box parts, what exacly? Are there better options available for G50 than stock 928 G28 rings if they're same?