Greater Spell Penetration
From Neversummer 4 Wiki
Type of Feat: General
Prerequisite: Spell Penetration
Required for: Epic Spell Penetration
Specifics: A +4 bonus to caster level checks is granted to the character when trying to beat a creature’s Spell Resistance.
Use: Automatic
Supercedes Spell Penetration under a Player Character's Feat list.
Epic Spell Penetration does not stack with Greater Spell Penetration despite the presence of both feats under the character's feat list.