Cayin 50-AT Tube Rolling KT88

Hi. Has anyone replaced the EL34 with KT88 power tubes in your 50-AT? The Cayin 55-AT model comes with the KT-88 and is said to have no other electrical or mechanical mods. Not sure if this is a dealer installed option but the amp is labeled 50-AT.
The KT88s are supposed to be a direct fit, sound richer, and provide an additional 5 watts in Pentode and 2 watts in triode.
Is this true? What has been your experience?
Thanks for your time.
no way it's unsafe and power transformer of the a50t will get v hot. i tried that before for 10 minutes only.