I bought a GM Tech2 scan tool clone from China, arrived the other day, installed the TIS2000 software on an old Dell D610 laptop with Windows XP (as the seller said it would only work on XP system), and am now successfully using it on my 1999 9-3 Vert, sierra and g8. No issues at all getting security access or anything.
So far I have run through the self tests, and connected to my Vert (which does not require Candi module although the tool does support Candi module) and all went well as expected. Was able to connect to laptop and TIS2000 via the serial connection and control the Tech2 scanner via the laptop. Also was able to marry all 4 door modules with my tech 2. FYI, Tech2 does not need software installation but need you install TIS2000 and the TIS2000 should be plugged to the laptop and should communicate with the Tech2.
Mine is from a Chinese shop named OBD2TOOL: http://www.obd2tool.com/goods-1568-GM+Tech2+GM+Scanner+-CANdi++TIS+(Works+for+GMSAABOPELSUZUKIISUZUHolden).html The seller Daisy He is good at questions and would email me back in minutes. I have been playing the scanner in the past few days, and it has been flawless and other friends, except one, have no issues with theirs either. That friend got the unit from Ebay and cannot connect to a laptop. I think it all depends on the seller. I saw some Ebay units work too. It is luck of the draw really. Maybe I was lucky and got a good clone.