Visited a friend last night. He has a Z2. I have a Z1. Now, I am pretty happy with my Z1. A few things annoy me but not many. Biggest issue must be fan noise. Now, my friends Z2 has almost silent running. Not sure how the Z2 does it. Is it sound deadening material, a quieter fan or something else ? Can I swap the fan in my Z1? Jus.