I have read a few threads mentioning these tuning box's are they any good? How much are they? And finally is it worth fitting one? The td4 to me is quite sluggish unless you keep it in the turbo and this only seems to have quite a narrow band so hardish work to keep it in the turbo. Not that I'm a boy racer but when towing especially uphill I find it a bit shaming being over taken by mopeds.