[steveproracing]

I happen to know how much a gearbox like the c4.1 costs to produce and unless cml were getting incredible discount then they were loosing about £10 on every one they sold. So to only have say five produced would cost nearly as much as buying a c4.2 kit. This is the only reason why they probably won't have any more gearboxes made! This leaves you with 3 choices.
1, obtain a 3d printed box with the hope it performs.
2 , spend aprox £100 on getting 1 box produced by the original machinist. (I can get the details of where they were produced if needed)
3, spend the £135 and get the new improved model with a better chassis and a gearbox that will last much longer and only cost £6 to replace!!