I am the proud owner of some nice KG 5.5's.
These are a REALLY great system and have given me a lot of enjoyment. As such this thread has become a little long!
So I've popped in a clickable index of sorts to help with navigation.
Phase 1: these are my 'beginners' improvements:
Part 1: My first basic steps I took to improve the physical aspects of the enclosures and some trial and error driver tweaks
Part 2: Taming the horn output.