If the stock air filter has been replaced with a K&N or other aftermarket filter you should hear it. If the stock cross-over air tube has been removed and you just have some type of cone filter on the end you should really hear it spool.
If the tamper resistant tape on the ECM has been broken, than its a 50/50 that the chip has been modded/changed.
Maybe one of the ECM modding guys (Nolan from the Canadian crew) can tell you what things would indicate that ECM has been modded.
Just my 2 cents!
:robot: