I must admit I quite like the falco...
I have done a few modifications over the couple of years to one or two of my bikes, and others as well.
Modifying your bike makes it an "Individual" and its about you when all is said and done.
The list of mods for these bikes is huge with the gen 1 mille being a good donor bike with the wheels and suspension set up etc.
The falco however will be more bike than you can even wish for even in standard form.
The mods you may choose will not give you massive gains in performance when going down the tuning route.
If you like to tinker you have the ideal bike.
I would strongly advise you don't jump in with both feet. Look at what other people have done then make a plan with what you want to do. STICK WITH IT!!!!!!
Second hand bits rarely come up but only usually when someone decides to sell up.
Advertise what you would like to buy someone passing may send you a pm if you are lucky but only if they have seen your post.
DON'T post links about stuff you have found. There are a lot that sit in the background watching but don't post, if you don't listen to this advice you will probably miss out and the vultures will be in faster than you can ever believe.
Modding a falco can be massively expensive... Believe me I have four.
Enjoy

Tolerance will be our undoing.