You may be missing my point...
There is a sealed section and unsealed section under the black base of the mini. The unsealed section is the section covering the wifi grill which is also the intake for the cooling system, and there is a sealed section for the main chamber which has the fan, heat sink CPU etc. the fan does not blow, it draws air from the unsealed chamber. The process of drawing air through the mini and pushing it out the back, and most importantly through the heat sink channels is the design.
So that is why I ask... Are you going to work with apples design and only pump air into the intake section of the wifi grill area or are you simply going to pump bulk air into the complete mini opening with the base off? The latter seems risky. It might drop CPU temps but you have many other temp points. Also you could get the flow of air all wrong.
I think you should only pump air into the intake chamber.