Since you asked, I will comment on the Busa & not where to invest your cash...You want to have some fun now, and something to get instant satisfaction out of...ok so here it goes.
1) Upgrade Brake lines & clutch lines, maybe rotors & new pads
2) New Wheels - Forged Aluminum or if it doesnt make you cry too much spend the $$$ for some CF wheels
3) HID
4) Store the factory plastics and go for the OPP Carbon Fiber body work or some of their other trick weaves
5) LM1
6) PC III usb, and throw in the usb timing unit
7) Penske Rear Shock, Ohlins forks or rebuild kit for your stock fork
8) A nice Hydrulic Lift
9) Baxley sport-chock
10) Pitbull front & rear stands
11) Forget Big Bore, get yourself a stroker kit
12) New tires
13) Become a donating member
14) S4L Billet sprocket cover
15) Spend a few grand with Coerce, Magical Racing, Catalyst, NWS...lots of neat goodies to drop cash on
16) ICEMANN Yellow Hi-Beam bulb
17) Throw some parts off to Vic for some trick powdercoating
18) Keep a few hundred in reserve to donate to members who have had an accident or fallen on hard times here at the board
19) A good Torque Wrench
20) Aftermarket exhaust...Your choice, because whatever I say someone will say Broks is the Best (Ya..right)
21) Engine Ice, Muzzy fan, relocate temp sensor
22) A few can of S100
23) Make the move to Synth oil,, and stock up on a few cases...use the OEM filter
24) Tobin Seats if cruising is your thing
25) Remove Pair valve & do small airbox mod if doing full exhaust
26) Get some quality Gear...You can spend a few grand there even before you snap on a $700.00 Helmet
27) rpm9001 makes some nice fairing screens
28) Scorpio Alarm
29) EK ZZZ chain and New Sprockets front and rear...maybe try a 42T in the rear...good for the giggle factor
30) Pazzo Levers...short or long, they are very trick
31) Ram Air seals to add a few more HP on the top-end
32) Gilles chain adjusters and Lifters
33) Ti or Anodized Aluminum bolts all the way around...lighter and very pretty to look at
34) Stem Stand is always nice
35) Wind Screen of some sort
36) Undertail with some bright LED's
37) A nice tank bag to use when needed
38) Gilles or Vortex rearsets...makes a huge difference in foot position and shifting
39) Keep looking for ways to shave weight off the Busa...never cheap and good way to blow serious coin real quick
40) Enjoy it, build it, customize it, make it your own, be original - And Don't Sell It!
Be safe, and post up lots of glossy pics to shows us your goodies.