Applying class feature to other class

[Pippin]

Hi there.

1. Can a Wilder 3/Psion 3 PC apply their Wild Surge +2 ability to their Psion powers?
2. Can a Wizard 5/Incantatrix 7/Cleric 5 PC apply their Instant Metamagic ability to their Cleric spells?

I'm looking for sources, if there are any. Thanks!

[Kayblis]

Depends completely on its wording.
For the Wilder question, Wild Surge mentions "whenever she manifests a power", so yeah, it can be used for any power the character has, even ones from other classes.
The Incantatrix ability is a somewhat different issue, and was altered between 3.0 and 3.5. The old 3.0 version(Magic of Faerun) calls specifically for Wizard, Sorcerer and Bard spells, so it's only usable with those classes' spells. The 3.5 version, the one everyone uses, only mentions prepared and spontaneous casting without ever talking about Arcane, Divine or specific classes, so it can by RAW be used for cleric spells.

[Pippin]

Thank you! That is exactly what I was hoping to hear, but I wanted confirmation that there was no hidden rule against it.