I would give it 5 stars if it were plug and play. It isnt per-say but it does in fact work and is very easy to use.
1. The tool can be used with the software provided or can be used with actual GMtsd tech2win subscription.
2. With the emulator provided you can do pretty much anything legit subscription can minus programming brand new modules to your car. This does not make the tool garbage...even if you have a gm technet subscription you still need a midi pass-through tool and this tool will do it.
3. As far as viruses and vpns go my technical opinion is that people's concerns are generally unjustified. If you have any experience with programming cards or say arduino boards there is nothing scary about installing some serial port drivers. Some manufactures use vpn for scan tools and module programming and the passthru tool has that capability.
Overall it saved me a few hundred dollars and dealing with the dealership, and it was kinda fun.
Was a little finicky to get to work correctly. Can find a few online walk throughs to help with order of software install. Once installed works exactly as it should. Can do all Tech2 functions on my 2002 Trans-Am. Pleased.
If you know what you're doing and what you're looking for, this will work for you.
I haven't fully tested it yet, but it seems to work.