Yep, I'm working on this one too! A few mm off the glass just isnt an option though. Tempered glass just won't accept anything being shaved off it. It is possible to sand it or trim a small amount off, but it becomes very unstable and won't take long before the whole thing shatters.
I have investigated this through every engineering contact I have (I'm ex military jet engineer and we used to use loads of different engineering companies and technologies.) And noone can cut or trim temprered.
The more working on it the better though, hopefully one of us will come up with a good method!
It is the 3dr btw.
I believe it was the guy making the 360 with the lotus chassis 'mydads360' that came up with the idea of using the Audi glass, so if that's right, all credit to you mate!