When should I change my air filter element?

[Luckalee]

I did a Zoodad, sort of... I drilled a single 3" hole instead of cutting out the shape of the snorkle. The only differece I notice is that now I don't even get a puff of smoke when I jump on it. I can't wait to tow the grade and see the real difference.

 

[CHPMustang]

The reaction time between hitting the pedal and the truck launching is much better with the grill support opened up