Muzzy just made the fan blades, so they push on and pull off of the fan motor shaft.
The fan in my '03 Gsxr1000 worked fine, but when I tilted it in my hand(not that it would ever go to that angle on the bike) the shaft had alot of in and out play, worn out bearings, so I swapped it with a spare fan that I had from a '17-'26 Gsxr1000.
The plug and bracket are different, but the motor size and frame mount holes are the same, so the newer motor fit into the old frame, and I soldered two wires.
I emailed Spal and a couple other companies several times, but could never get cfm ratings(cubic feet per minute of air flow) from anyone, however, I would *assume* a newer model fan would flow as much or more than the older models.
The fan works great in my '03 now, and cycles on and off as needed, with the bike never getting too hot, or anywhwere close to it.
I have a manual on/off switch too, but have not needed it.
Maybe on a very hot day, and in slow traffic the bike would run hotter, but so far so good.
The easiest way for you to add a second fan is with a Gen2 right side fan, or even just the bracket that fan sits in.
The aluminum blade is just an aftermarket option, if you want to spend the extra.
Does the aluminum Muzzy blade help to cool things down a little?
I cannot say for sure, but the mod was common in the Gen1 days, and seemed to be an improvement, as either the aluminum blade was more rigid than the plastic blade at high temperatures, and did not deform/lower cfm's, and/or the aluminum blade's shape was an improvement over the plastic blade's shape, and the aluminum blade could move a slightly higher amount of cfm.
I'm all for overkill, and cool mods, so I would get a right side Gen2 fan with bracket, and a Muzzy aluminum blade.
The Muzzy blade from the R1 should be the same part that fits the Gen1 Busa, with the same shaft diameter as most Japanese sportbike fans in the last 20 years or more, with the only real differences between brand and engine sizes being the mounting brackets, with the fans themselves being basically the same design.
The fan's electric motors rarely fail too, so the age or mileage isn't always a determining factor in how good of a usef part it may or may not be, condition wise.
You have alot of fan options.