Umm... Have you BEEN in the US? Random DUI checkpoints have been going on in all 50 states for years, and have been (somehow) ruled 'constitutional' by courts all over the country. Near the Mexican/US border, immigration checkpoints are very common, as well.
OP, I stand by my earlier post- go online (or make a phone call) and determine exactly what code/statute/law you're accused of breaking. This, and only this, will tell you how you should go about fighting the citation.
Be prepared, though, as a favorite in the states is to have a vague law that says it's illegal to modify your exhaust, so pretty much anyone is stuck. Also, they might have a vague sound level law with no db limit- how do you fight that? It's all opinion, and you can bet any judge would automatically side with a cop.
You just won't know anything until you know what you were cited for. Heck, if he did write you for 'no mufflers', then you're fine. Take your own photo, and maybe one from Roush's website, and there you go- they are mufflers. They might do very little, but they ARE mufflers!
Negative sir. DUI checkpoints are illegal where I live. Sent from AutoGuide.com Free App