Genesis fan here, both Genesis Physics, and Genesis the band! Oh yeah, and new here!
I've had a pair of Genesis II's for about the past 7 years. Shortly after getting them, I upgraded the crossovers with a cascade bypass design, using three caps, each increasing in quality and smaller in value (Dayton 1% 6.8uF, Jantzen Standard 2.2uF, Jantzen Superior 1.0uF), along with an upgraded Jantzen 18awg inductor. Also upgraded the rear terminal plate, added quality binding posts and upgraded the internal wiring.
Last weekend, I decided to do some upgrading again and went with a single Jantzen Superior Z-Cap 10uF and a Jantzen 16awg wax-foil inductor.