Optimise what you have .

This is such a contentious subject.

Lots of people spend a fortune on performance, and that's entirely up to them, and then run their bike with worn chains and sprockets and a slipping clutch.

I'm not preaching but before you do anything, get the basics right.

Make sure everything is adjusted correctly ergonomically. Clutch bite point, brakes, no good if you can't control all that performance if you can't turn in. Handle bar position, rear brake and gear selector pedals right.

Good lubricated and clean chain and sprockets. Oil level correct, all the nuts and bolts checked,no frayed or cracked worn through cables. Forks serviced and seals oil tight. Head bearings cleaned greased and adjusted correctly, all the suspension components on the rear greased up and operating correctly and set up. Wheel bearings in good condition and tyres the best you can run and inflated correctly.

None of it costs that much. Just time,focus and TLC.

After that, learn to ride it past its limits ,then spend the money.