83 oz/in is indeed the spec at 6.0 volts......for 9550
Futaba made these 2 servos by using the same material, however, the differents are their SIZE and WEIGHT...
I am sure you can get all the information about the 9550 servos, it is MORE then good/strong/fast enough for typical 1/10 scale 200mm touring car........and of course 190mm elect TC.
If you have a heavier then normal chassis, try the 9550, I used it on my NTC3 (made it WAY below legal weight) and on my R40 (tried to save some weight)....the 9550 works just as good as my previous high torque high speed metal gear 9303 servos, but WAY lighter (any much faster)
About 9450....same spec, but have more torque, of course, that will work on almost ANYTHING except those Titanium HPI Savage or REVO........but that is one great standard size servo as well.
I think TOWER HOBBIES spec are very accurate compare to the Futaba (probably got that direct from Futaba site...)
Speed: .14 Sec/60 Deg @ 4.8V or .11 sec/60 deg @ 6V
Torque: 67 oz/in @ 4.8V - 83 oz/in @ 6V
(4.8 kg/cm @ 4.8V - 6.0 kg/cm @ 6V)
Weight: 1.6 oz (45g)
Length: 1.6" (41mm)
Width: 0.8" (20mm)
Height: 1.0" (25mm)