Thanks for the responses, tbh i wouldn't care if it was straight cut or not, as long as it doesn't break easily. Having read about offerings from Quaife/Bara/R&D/Fixit none of them inspire me with a great deal of confidence and each seem to have their own pitfalls, so I'm opting for the Oppliger kit which seems to be a good all round kit.

Do the other boxes have a spacer/strengethening plate?