Upon startup my RX8 runs fine, but once it warms up and I start driving for a bit it loses almost all accelleration and sounds like it's struggling to move. I have replaced the spark plugs and the Catalytic is fine but I'm wondering if the problem is being caused by my air filter possibly?

 

highly doubt it has anything to do with your air filter

check your coils, they need replacing frequently

 

Dinsum....what coils do u speak of

 

Ignition coils.