There are a huge number of things that have minor effects on the sound of any piece of gear, especially no-feedback gear like most of ours. But when a minor change hits you just right it can be immensely satisfying!
The main point of modifying designs is IMHO education - learning to listen, and learning what changes have what effect. For some this is a powerful inducement, for others it's just a distraction from the music. We are proud of the performance of our products in stock form - as I said, most mods have a minor effect. But we are also big believers in the personal power that comes from a deeper understanding of something one is passionate about.
The few that have the greatest positive effect as heard by a majority of listeners (and usually some actual measured data to back it up) wind up as upgrade kits - so if you are starting from ground zero, that is a more reliable option. Also, we will support those mods. Other mods will void the warranty, and make our in-house repair service more expensive. But as long as you take responsibility for the consequences of your experiments, we do not discourage such experiments, and the Forum allows a community to share their learning.