None of my sports cars have had license plates on the front, only got hassled for it when I was young. Got pulled over a lot more then too.
About 110k on a 71 240z
About 120k on a 69 Vette (turn signals never worked on this one either)
17k on the 370z so far.
No pull-overs for license, no warnings.
Don't be an idiot, be nice and polite to the cop and don't get out of the vehicle. They really don't like it when you do that.