I think its purely age related tiff as both have only plug in stage 3 chips, 21psi so guessing 290+bhp.

£25 each from woodford and £28 from Fords with discount.

The reason he wants something a bit stronger is because on one of the cars the turbo has just failed (missing 2 turbine blades) and he's paranoid the dump valve has contributed towards it.

So thats really why i'm asking if its possible to rebuild the std dump valve for purely better reliabilty.