Can you make a Guardian Spirit an actual Familiar?

[Reksew_Trebla]

Say you have the Summon Guardian Spirit feat, Improved Familiar feat, and you spend the time and resources to track down the Spirit's plane, go there, and convince them to go to the Material Plane with you. Could you make them your Familiar, or would the Guardian Spirit template make them non-eligible to be a Familiar?

[Melkiador]

The intent is no. "Only a normal, unmodified animal may become a familiar."