well i have to say ohlins will be the best but out of mosts price range.
i personally think the top mount shaft style dampers work better. you know because a shaft that moves back and forth with fluid in it will usually never fail. n i still dont understand how they make a damper without a shaft?
anyway i have also heard alot of good things about the GPR becaseu they where the first and i still think one of the few dampers for an 05 zx. and everyone on my kawi forum got one and all said good things about it and no problmes.
and def ask speedwerks.com first b4 u buy anything. good prices, for past 2 things i got from them the best prices on the net. great customer service. and if you live near them the shipping is that fast its unbelievable.