Hi chap im having the same problem im running a zvh around the 300 bhp mark, with a standard box and basicly f**ked it, asked on here and on fiestaturbo.com and got alot of mixed advice alot said mk1 focus rs box a few said uprate the standard or ib5 or mtx but focus rs and mtx as you said take alot of work to fit and money, personly im gonna try an ib5 box and uprate the thing see how that works out unless i find a better box forsale on here as they do come up alot it seems, as for turbo i run a t34 16 fin turbo with 360 bearing stagard oil seal, with standard manifold and downpipe and ran beaut, i am in the process of fitting a jamsport manifokd and custome downpipe with external wastegate, i see your in leicester aswell where abouts as ive never seen one around here?