I see where they list the 163R for the GT500. Is this special order?New heat sink clip ons seem to do the trick.
If you have a problematic TB after heat soak of any make, I’d try this first.
Came with my 163R but it’s a common RC car motor heat sink.
As far as the heat sink, I don't see a down side to trying this. If anyone is curious, I just measured the motor diameter at 37mm. No shortage of them on ebay.