Main thing i found with the old gearbox issues was....
1- broken engine mount every time i stripped 2nd gear it was a hair line fracture in the 3 piece engine mount.
2- the plastic brace from the radio tray to the layshaft bulk head screw stripped and comes out or loose and moves on the radio tray alowing the car to flex front to back.
They were the main things also gear shimming but that is standard make sure your pinions are all the way onto your spur's
the new sl6 gear box i have not seen much of a improvement!!!!
Yes there is less rotational mass i get that the change is less consistent and the gears still strip
here is what i found to get the sl6 to work----
1- superglue the 2nd gear screws into the housing (why you ask??)
these screws come loose so fast and create a elongated hole on the 2nd gear housing alowing the 2nd gear to move back and forward good luck getting a good mesh after that the gear will just strip.
2- the little grub screws that we all never used (well some did) that adjust the hight of the 2 speed shoes need to be checked and in my case glued as they come loose and alows the 2speed shoe carrier to float and become loose this made the gear box very inconsistent like very once these grub screws were tightened up the gear box was great.
3- shim that bastard yes shim the gear box right if its not shimmed right there is too much play in the layshaft and your spur's will hit the pinion if not your 2nd gear housing will hit the layshaft bulkhead so shimming here is essential.
so you can see you can have a 733 with out stripping gears but it is an effort.
god luck and the 733 is fast and a good car to own but like everything in this hobby (sport
) you need to keep ontop of these things.
Serpents stripping gears can be resolved quick go run a r4 and you will be doing a diff change in a 10min qualify
mugen stripping gears and doing diff's locally here
so every car has there issues.