so with the ExtremeAire compressor(the 100% duty cycle one) do you have to have an air tank? or could you just run it without one? would it be a lot slower?

Also, is there a cheaper place to buy them other than there wedsite for 379 plus shipping? (which comes out to 406 ish)

because with my truck, it would be a pain to try to find a spot for the compressor AND a tank, without getting either damaged.

 

The tank will get you 2 things...
1) A reserve of compressed-air when you start using it.
2) A higher CFM at a higher PSI - *but only for a short burst*.

In other words, your first tire might fill faster when you have the tank...but the others will take the same amount of time.