Mate, it sounds like you guys have a bit of history. But to someone like me just entering this thread to look for info, it also sounded incredibly rude. I think some people forget that the valve spring not only controls the entire valve train, but it also has to control itself, as each coil has weight and inertia, and stores kinetic energy. If you can lighten the spring itself – as well as the retainer – then that helps. It's also the premise for running as close to coil bind as you can.