Colorado license plate? Probable cause for a stop lol

[Great-Kazoo]

I think if they had been complete a-holes, I might have taken some action.

They searched your vehicle based on a dog's belief there were drugs . While dogs do have a good track record. Why the hell you allowed them to do anything without a warrant, is confusing.
The only a-h i'm seeing iis you consenting to a search, AND OFFERING TO ASSIST.

Yo man you forgot the tail lights.

I know you're a newer member, but anyone else mention you can refuse a search? Get out of the car and lock your keys in it, if it's an older vehicle, walk to curb or off shoulder and sit down.