What have people done to there box's on either escos's or saph 4x4's

Spec when the car is back together will be NMS low lag head, standard bottom end, t38 and 403's hopefully around 400bhp

I spoke to a few places today and was horried that its gonna cost around 5.5 k to have a decent spec box and front diff.

So what have pepole done to theres. Whats the priority and are there any cheaper alternatives.

Thanks Jamie