Can this server config take ND6.5?

Hi,

I am planning for upgrades from r5 to r6, however just would like all your opinion on the recommended hardware, pls help to comment?

SUN E450

4 X 296MHZ CPU

4GB RAM

2 internal hd for OS etc

1 A1000 hard disk raid - raid 5

Also, what’s the best OS for 6.5 - Solaris 8 or …9?

Thank you.