I don't post too much - but read quite a bit here for info. Like many others, I fear losing a PCM during a download using LT1 EDIT. I have downloaded many times, but hold my breath each time fearing "Losing Communications". According to others here, it appears that even if you switch the VIN on a new PCM, LT1 EDIT's will still show "UNLICENSED PCM". Hypothetically Tunercat's WinFlash from Tunercat.com/downloads would work to download LT1-edited files. They have a free trial download, but the $20 they want to be legit is nothing compared to the hassel it could save.

 

I was informed that LT1Edit references a hardcoded number in the PCM, and will not allow you to switch PCMs. It is a PITA, but so is LT1Edit overall.
Tunercat is far more flexible, and is my choice for the future.

 

+1 for tunercat. I have their software and it is really easy to use.