As to the symptoms - lack of power when the motor is under heavy load (like when you are passing or accellerating), lack of high rpm power, possible pinging/detonation under load, stalling or missing.
You might get one or all of the symptoms, might be intermittant.
With the right tools to remove the lines, it is very easy to change these filters. I got an assorted set of line tools from Auto Zone for like $10 (use the grey one). Don't try it without line removal tools. Search on the board for instructions if you are not sure how to get the lines off.