I have an 07 XC (which is styled like an Edge so a bit like your 92), and an 07 Switchback which is an IQ similar to the shift in your picture. 1)Yes the windshield of the IQ is smaller, but the higher seat and better position of the handlebars of the IQ are easier on the legs after a long day. On those cold fast trail or lake days, you have to keep the helmet closed and the defog plugged in on the IQ. 2)The handling in deep snow is better on the IQ. 3) I think the hp of these two would be similar although I don't have the specs. My two sleds are 100 hp and 120hp, both liquid cooled. My two cents.
The 550 fan is a great motor, but its no liquid. The 550 will ride a lot better then your old efi, but wont blow its doors off in performance. As a bonus the 550 will have PERC. I believe you can get big tall windshields for them.