i just thought of another one apart from the boxster one, go with a mate, but have him hide outside, but where he can see you, you go in browse around for a bit, then either wait for one of the sales reps to come up to you, or call one of them over and start talking, asking lots of questions about the car, then while mid conversation, drop a little signal, touch your ear or something, to let your friends know to call you, at which point, politely say 'pardon me one second..' answer and it start talking out of your arse
'look! i told you before, drop the Williams account, that bottom feeder thinks he can run my company because he put 800 grand in, f*ck him, Charletons got 6 mill ready to roll, and if you call me on my day off again, you can go find another job, now F@#$ oFF!'
"sorry bout that, so how do i get a drive of this thing again?"
*foreign accent might help too, but that might be going too far?*
that said if you walk in with a sawn off they arent likely to say no either