Keep in mind most manufacturers will refuse to service "modded" equipment, because the quality of the mods is all over the place. Some mods actually damage the circuit, or make it unstable and failure prone.
If a manufacturer sees that when they open the can, they’ll close it up and send it back. It’s far more expensive to repair and restore a modded unit back to factory spec than simply build a new one from scratch.
Even when repairing a factory-stock unit, at some point, the repair techs will write it off and swap in new or refurbished circuit boards instead of wasting any more time on a unit with weird untraceable defects. This applies with even more force to mods with no documentation and unknown quality parts.
New-build procedures, at the factory, are rationalized and done to a strict protocol if the manufacturer knows what they are doing (hopefully yes). Anything out of the ordinary takes up time, costs money, and invites errors. This applies with more force to unknown mods which are secret or undocumented. Once any unit is modified, you need to turn to the modifier if you want service in the future.
