The black eccentrics are from the early top cats/mk1 cougars I believe. White was on the cougar 2 and works models. I dont think there is any advantage just different colour. Although the white came on the pro-diff so there could be a difference is size but not 100%
The front of the MK1 makes it a longer wheel base over the swept back cougar 2 wishbones. Nothing else is any different just the wishbones. Bulkheads, top brackets etc.... all the same for all cougars.
The works gear box was moved back on the chassis to try and gain extra grip in the wet or dirt tracks. This is were the cougar lost out to the rc10......
On the works gear box the motor slots are vertical not horizontal like the standard cougar box. So to adjust the gear mesh you move the motor up and down. I dont think you would notice a real difference in the works box other than a pro-diff. But that is if you can find one plus the cost of one as well.
It also depends on how much you will be running it. Just at Iconic meets or your every meet......
