Warning: This is 3.0 Edition material. It is possible that there is more recent 3.5 Edition version.
Inaccurate?

Boost Spell Resistance

( Book of Vile Darkness, p. 47)

[General]

By making a deal with an evil power, the character makes himself even more resistant to magic.

Prerequisite

Any evil alignment,

Benefit

If the character already has innate spell resistance, he gains a +2 profane bonus to his existing spell resistance score.