Spellthiefs (Complete Adventurer variant, p. 13) can not apply metamagic feats to stolen spells they posses.
The Steal Spell’s description reads, in part:
A spellthief can’t apply metamagic feats or other effects to the stolen spell unless the specific spell stolen was prepared with such an effect. For example, a spellthief of 6th level or higher could steal a wizard’s empowered magic missile, but only if he specifically chose to steal empowered magic missile. If he chose to steal an unmodified magic missile, he couldn’t steal an empowered magic missile, a silent magic missile, or any other metamagic form of the spell. A spellthief couldn’t steal an empowered magic missile from a sorcerer, since the sorcerer applies metamagic effects upon casting and thus has no prepared empowered magic missile spell.
Does this description refer to metamagic feats in general?
Would it make any difference to apply a metamagic feat through the usage of a metamagic rod?