Upgrading can be done one item at a time too.
I would start with S.S. brake lines. This will make a big difference in both feel and power and it's pretty cheap. There are many options but IMHO they are all decent so just pick one. I'm currently running kevlar lines - don't waste your money on these. They are fine but not that much better than S.S. All you need to know skill-wise is how to bleed the brakes to install yourself.
Next are the brake pads
@sixpack577 referred you to. These are both cheap and easy to install, so I would do all this at one time to get a bigger improvement.
At this point, you will have serviceable brakes for the street. If you are 200+ lbs or ride 2-up, the OEM brakes are dangerous IMO. It will essentially fix the weak OEM stoppers and make them serviceable. Remember, a free way to get better brakes is to get your suspension adjusted properly, and conversely no matter how good the brake parts are if the bike stands on its nose when you touch the lever it's no good.
But great brakes are about power and control, so next is the MC and the Brembo is the ticket here brother. The Brembo is basically plug-and-play and it's on a lot of Busas already. The basic RCS will make your brakes amazing and you will be amazed at the confidence boost you will get.
As long as the rotors are not worn or warped, they don't matter all that much. I ran the OEMs with my Brembo Rcs for 2 years and only upgraded for the bling. The OEM calipers are also fine. That's not to say my GP4 Brembo calipers and Brembo Rotors can't stop you so quick your false teeth bounce off the inside or your shield, just that that's a huge amount of money for a relatively small improvement you may not even use.
BTW: I modeled my setup after
@GIXERHP !
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