One is the T56 Magnum you can order and have next day'd if needed and the trans costs $2895 instead of $4300+. The T56 is essentially geared identical to an 833 but with 2 extra OD gears. Plus the shifting of a T56 is snick,snick not row,row like an 833. If I had a numbers matching rarity that I wanted to drive I would go with the Passon if,if,if I could get one. Some people require a bolt in trans so if that is the case the $4300 makes sense. All 6 of my gears are very usable indeed.