I would suggest cartridges and rear shock upgrades if money is no object.
Give these guys a call for some info:
http://www.cyclemall.net
http://www.sonicsprings.com/catalog/
http://www.traxxion.com
http://www.racetech.com
http://www.jrishocks.com
I talked to them for info and pricing options for my 300.
options:
gsxr shock + sonic springs = $115 (parts only)
gsxr shock + springs + emulator = $260ish (parts only)
automall custom fork tuning + jri shock = $1200 (they don't charge for labor but its in CA)
cartridge + rear shock = from $1500 - $3000 (best performance option, money no object)
Those are quoted prices for a ninja 300 and should be more or less the same for a ninja 250.
I would suggest you look into these options before a fork swap.