Owning both the 63 and 82 Id say the 82 is alittle better but barley, it runs alittle higher RPM's with a 14x4w and its a tad light then the 63, but the 63 has great fuel economy, its a toss but IMHO the 82 is the better, And I promise the 50SX or 46AX dont compare with the 82 or 63 in absolute thrust.
A good 46-50 2 stroke will pull about 7 1/2 lbs of thrust, the 82 pulls 9lbs and the 63 about 8.9 lbs.