My 2000 Hayabusa Supebike (with OE aluminum subframe) scaled at an honest 475 pounds wet which was about 75 pounds lighter than it's original 550 pound wet weight. It remained street legal, with the license plate mounted to the back of the battery box, minimalist lighting (individual bare LED tail/stop/turn lamps, and a pair of miniscule driving lamps hose-clamped to the upper fork legs under the fairing.
I used a Muzzy 4-1 titanium exhaust system, Marvic Penta II magnesium racing wheels, Sharkskinz race bodywork, and removal of all of the stupid heavy stuff that comes with the Hayabusa, to include:
Solid steel bar ends
Tool kit
Tank prop rod
ALL that black plastic under the tail, right up to the battery box
Engine counterbalancer
Footpeg weights
B-pegs
Grab handle
PAIR system
Airbox interior (large box mod)
Flapper valve, link, servo, vacuum line, etc.
OE Frankenstein bolts
2 of four grab handle bolts
...and so on.
The only expensive part was the wheels (the exhaust system wasn't really that expensive)
In the end, it was only about 25 pounds heavier than a stock Gixxer 1000, and had more horsepower.
On the street, at track day pace, or at novice race pace, it gave up nothing to 1000 cc bikes. At an expert's race pace, the additional 2.9" of wheelbase, and even more so, the width of the engine, were significant issues. This ultimately drove me to replace it with the R1, which was instantly 3 seconds a lap faster, simply because the engine was so much narrower.