Weblogic 8.1 Server Setup

For few weeks i have been involved in the upgrade from weblogic 5.1 --> 8.1
I have to dig in a lot of places to get answers.
My research shows that the two best reasons to move to WL 8.1
a) SplitDir structure
b) APP-INF structure.
One thing , I did not like is that , a few classes like Starup classes still need to be loaded
using SERVERCLASSPATH.