For serious competition, it'll be a little under-powered and heavier compared to the current crop of 450's over the past 5-6 yrs. If just using it for track-day fun. GO FOR IT!
Bonus is that KTM supermoto parts bolt right on.
For extra sharp handling (if running 17's wnd/or a 16.5 front) pick up a 14mm offset triple clamp (older KTM 125's ran them), or the factory KTM 18mm/20mm triple.
I loved the 14mm with a 16.5 on my old FX450. Great handling bike.
FWIW, I really liked the FX450, except when it came to jumping...it always felt like it gained 20lbs the second it was in the air. LOL!
Enjoy!