Swapping TB's what issues will I have?
 

A customer of mine has an 03 2500hd 6.0 105k mile truck with a reoccuring p1516 Throttle actuator position performance code. I've cleaned grounds G103 and G104 on the engine and he's replaced the TB harness, with no change in behavior.
He can get an o5 GTO 6.0 tb for $30-40 from a coworker who changed it for a larger dia TB.
It should bolt up to the truck, but will I have to modify anything because he has an AEM or K&N CAI?

It has a custom tune from John Spears - www.speartech.com.
Will the ECM have to be reprogrammed for the truck to run correctly?
Thanks for any help guys!