Look bud, since I'm your age, I sympathize. It can be done. But since you are going the bone-headed route, Im not tempted to tell you the key factor :rick:
So far I've driven a 645ci and an Audi TT roadster. And I'm 16.
Anyways, 645ci. I cheated somewhat. I have a fake ID from my friend whos 20. Its his old drivers license. He is my body double pretty much, so I use it for booze etc. Anywho I called ahead(2 days in advance) and said I saw the add in the newspaper for the 645ci, and I made an appointment etc to drive it. I wore a polo shirt with jeans, loafers, and an Omega watch(my grandpas, I inherited it). I still got a sketchy look from the salesman, and he came out with me, but I still got to boot the car around. I had some old bussiness card stock laying around, so I printed up a car on my dads laser printer (Derek Kreindler "Consultant"), so that went ok. He called me back a week later, I told him I bought an SL55 instead
The TT was almost a joke, except for one minor altercation. I was on a feild trip and after that I was bored, and the girl I was with had to leave or some B.S. I knew Audi had 2002 TT's left in stock, so I just figured what the hell. The salesman couldnt have been more than 23 or 24, and he knew what I was up to. I gave him my real license, and he told me it may be difficult to get me a drive. He had to talk to the manager, who pretty much interrogated me. I told him that I knew Audi was desperate to dump the TT's and that he could potentially save them from being entered into used car or auction inventory by letting me drive them. He relented, although I had to leave me Bank Card with them (

). In the end, the TT wasnt that impressive.