My air pump sounds like poop. It sounds like it is grinding itself a part when you rev the engine. If I remove the air-pump and the cat with a stock computer will I have problems. I would get an Rx7 extreme resonated mid-pipe to replace the cat.
Otherwise, I do have an extended warranty that should cover the air-pump, but if it doesnt I am not buying a new one..

 

Without a airpump you are going to clog your cat. Aftermarket or stock.

 

If your warranty won't cover it, just buy a used one. They are usually selling for around $50.

 

I have a used one for sale. will sell it for 75 shipped.