I've read a lot and watched a number of YouTube videos on the reasons why one should 'upgrade' your Defender performance with a boost pin and/or ring. Invariably, the suppliers of these items are all over the forums and social media promoting and justifying the case for doing these upgrades; as someone who also runs a business, I totally 'get' that and why should they not? Let me just say now that I'm a novice when it comes to engine tuning and optimising and that's why I'm posting this open question because, to date, whilst I've seen individuals on this forum report definite performance improvements, I haven't seen a 'before and 'after' comparison particularly with a boost ring installed after a boost pin 'upgrade'. Are upgrades happening on many engines where the core fuel management components are not optimised to start with and, so, something like a boost pin and/or boost ring will inevitably make a difference? In other words, should we not be ensuring the injector pump, etc, is set as good as we can get it or even have a specialist bench-check it first? There's a nice little earner going on here with, what looks like to me, over-priced bits of CNC'd metal (OK, maybe decent grade metals, etc, but still over-priced IMHO); or maybe not.