For some of these (Celestial Hawk, Dire Rat, Fiendish Viper) the special ability is "obviously" the same as their non-upgraded version; but what about the others (Stirges, Elementals, etc) that have no mention in their monster description sa to any familiar bonuses.
Imps at least have a brief mention of some powers, but no indication as to their associated bonuses.
So the question is:
What special ability do non-templatised improved familiars give? None? Is it just a prestige thing?
Also; is my assumption that the templatised familiars give the same special ability as their normal creature type. Is this correct?