recommended upgraded
Few things...
1. Get the diff orings from tony's screws. This will eliminate the issues with leaky diff.
2. Get the aluminum front shock tower as I have had the stocks ones crack.
3. There have been issues with the chassis cracking at the flywheel opening. I had this issue with my 6 in February 2009, but since changing the chassis and using the kingheads extended motor mount have not had the issue.
Other than this you pretty much have to run into a brick wall for it to fail.