GPZ Intake and Exhaust Mods

[keith fraser]

I have been considering intake and exhaust options. I came across this page on the muzzy site,  http://www.muzzys.com/zrxdyno/index.html , showing the effects of different mods on a zrx 1100. It's my understanding the gpz and zrx motors are very similar.
There isn't much difference in power between the stage 1 and stage 3. I would like to stay with the stage 1 but would like to replace the stock air filter with a K&N. The air filter is tiny, only about 2/3rds the size of the filter in my old Ninja. K&N doesn't list an air filter for the GPZ, anyone know of a compatible K&N part #?
If I did decide to go to a stage 3 would I need to buy the reed block off plates? Is there anything else that would need to blocked off or disabled?
Unless I find a really good price on a used exhaust system I will probably buy the v&h supersport. It fits my budget and is the only black pipe I have been able to find. Does anyone know of any dyno charts for the v&h pipe? Or any other pipe and jetting combos? 
Also I have seen a couple sites recommending changing out the plastic radiator fan for an aluminum aftermarket one, is it really necessary?
Keith