My admin says that the 2.6 branch of the kernel really isn't ready for production servers. That's just his opinion... I don't know what anyone else thinks. But I trust my admin
Also, GRSecurity may be no longer in development (see the notice at www.grsecurity.net). I use it on my servers with no problems, but we're gonna switch to LIDS I think. Try searching for LIDS or OpenWall kernel patches on Google.