The Duke Suite was the most challenging for me because of all the different keyboard sounds, and the multi-layered parts. Contrary to popular opinion among Genesis anoraks (no disrespect), Tony Banks' parts represent very little technical challenge to a classically trained pianist, especially the early stuff. He didn't even use a synth before "Selling Engand". People used to be amazed when we played stuff like "Duke's Travels", but Tony's solo is little more than rudimentary scales and arpeggios.
The band does indeed have a website; in fact, I continue to maintain it even though I haven't been in the band since 2003:
http://www.inthecage.co.uk