Hi there I saw in a couple of posts mention that the six speed box is stronger than the five speed found in the 13 and 14. I also saw that the issue is with the circlips becoming loose and causing damage. I am living in Trinidad in the West Indies and currently have an S15 that I am upgrading and would like the gearbox to handle over 500HP although I'm shooting for 450HP. Do you'll have any sort of pictures or direction you can give me as to what needs to be done to the box to allow it to handle the bigger circlip? I picked up an extra six speed box for a ridiculous price, the equivalent of $80USD, yep seriously, so I wanna open it and do the needed and used this box on the rebuild. Thanks in advance for your help.