[Finnster]

Chris and Jerry are right. Don't walk in there challenging the cop and calibrations and nonsense like that. Even if you could prove it (highly doubtful,) you have to remember these guys know and work with all these same cops. You'll come off as some smartass kid questioning all of their integrity. Plus who's to say its not 10mph over, and they should write you a bigger ticket? It happens...

Reminds me of this coworker (african guy) who got busted doing 25 over in Newark, and tried going in there claiming the cop was racist.
We told him not to do it, my other coworker's bro was a Newark cop telling him not to do it, and he did it anyway. Did not go well. lol

As far as lawyers go, depends what its worth to you. There are cheap traffic lawyers, but prolly not too warranted here. They can help talk the DA down. When in my bro was in HS, he ended up getting a 25 pt ticket (you lose it @ 4pts in CO) where a cop eventually ended up splayed on his hood screaming Asshole! Stop! Asshole! Lawyer got it down to 2pts and defective vehicle and he kept his license (and luckily my parents let him keep his head.)

So yes, you are best off just talking to them politely and respectively. Don't make demands, don't be cute, don't cop a bunch of sad stories (they've heard them all), admit you were being an idiot, and hope for some leniency. Basically show you'll take responsibility for your actions and recognize your mistake. If they figure you're someone they will not likely see back there again, they'll cut you some slack.