Heh, unless you work for a GM dealership, you have NO idea how bad GM is at IT. Their dealer-side website still does not officially support anything other than IE8. Business reporting relies on ActiveX integration with Excel, and only works properly with Excel 2000 and 2003. It can be made to work under 2007, but they don't support anything higher. Parts of the service-related workbenches still use VBScript. It used to be accessible only over a super-slow satellite link, but they changed that a few years ago, thank god.
To be fair, though, Toyota's web back-end, Dealer Daily, is even worse. IE-only, accessible only through a dedicated T1 which may not be used for anything else (but which you still pay full price for, of course). Blank page under anything other than IE.
Come to think of it, a lot of dealership stuff is locked on IE. Dealertrack (intentionally locks out non-IE browsers), Dealersocket CRM (featured-limited under non-IE browsers). ADP is the biggest supplier of dealership management software in the US and most of their stuff is entirely reliant on IE.
It's a pathetic state of affairs.