Dcr

To that last part... DCR is important IMO, but as you note - it changes. You can put in parts to give you a certain DCR and end up creating a lot of detonation in the midrange. So using that knowledge properly is as important as having it. Over the last year or so I've pulled away from high DCR builds. There's really no reason to push limits - you can make safe power and efficiency in other ways.