The short answer to this is DON'T. But that said take into account the usual Experience cost of the statistic points and the requirements and limitations of the particular reward. If you are going to give Statistic's away then make it last for a period of time - 1 year, until the next blue moon, until 1 Heat 810, etc.
Think about doing it in steps so that people at the cap of the stat are different from those with room to move. Think about the use of the stat by the characters. Try not to fill all of a characters flaws. Weakness for a PC is a good thing, encouraging them into groups.