Titus, here are some of the problems with two of your suggestions:
- Filing a complaint against the cop:
Yes, it could hurt his/her chances for promotion. And in a large department, it will cause a bunch (30 or more) hours to be spent on investigating the complaint, and could result in corrective action, although the vast majority of complaints result in no discipline to the officer.
But it could have a significant and unwanted reaction on the part of that cop and potentially others in the cop's department that would make the procedure detrimental to most of the posters here. First, the citizen should be squeaky clean before filing such a complaint. All the cop or the police department has to do is to pay extra attention to the complainant and catch him/her in illegal activity. Then not only does the complaint now come from a person who has been arrested and charged with a crime--soon to be called a criminal, after conviction--but now the complainant has to deal with these charges.
I know you pointed out that much of your advice is not valid for those who appear to be criminals or druggies, but it's important to consider that this particular advice is also generally not valid for someone who is committing a crime, even if that crime is merely the possession, transport, and/or purchase of illegal drugs.
Next, here is a phrase that's food for thought: "The cops are the largest gang in the city." Would you fuck with a gang member? If standing up for your rights was important enough to you, the answer might be, "Yes." But that's not the position most people are in. Most people are simply trying to get through the day. By filing a complaint, you've made an enemy. Especially in a small town or with a small department, you will make a big wave when you do so. A cop who is a bad apple in his/her conduct on the job is probably a bad apple off the job as well. It's a bad idea for most people. UNLESS, that is, the cop's conduct is so egregious that it results in physical injury, phony criminal charges, or some other legally-actionable damages. In that case, the entire process should be handled by your lawyer.
Obviously, it takes brave people to stand up for their rights and help ensure that bad cops are weeded out. But a user of illegal drugs is not usually the one who should be that brave person.
- Closing the door behind you and locking it:
It's similar to what I just wrote above. You just fucked with the cop. You made his or her job harder. You challenged his or her authority. You put a physical barrier between the cop and the interior of the car. This has legal and personal implications.
Legal: In certain circumstances, the cop has a right to search the space within your immediate control (aka your "wingspan") to make sure you don't have a weapon. Once you're out of the car, the items inside are arguably no longer within your reach, but now, even to an honest cop, you've aroused suspicion about what's inside your car. Could you have a weapon in there? How quickly could you unlock your door and grab it? You will cause even a good cop to be scared, angry, and suspecting you of hiding something.
Personal: You fucked with me, so now it's a must that I fuck with you, asshole. This could be anything from a very thorough search of your entire vehicle, to waiting until a drug dog arrives to sniff you and the vehicle, to a beating. This runs contrary to your previously-posted good advice about being the type of citizen that appears to be docile, harmless, and cooperative, except when it comes to consenting to a search and otherwise politely but firmly standing up for your rights.
Also, make sure, when pulled over, that you do NOT exit the vehicle unless the cop orders you to do so. I know your approach is to follow the cop's orders exactly (the exceptions being verbally not consenting to a search and asking whether you're free to go)--and this is a great way to avoid further trouble. But it's worth pointing this out to avoid confusion.
This doesn't mean that other suggestions of yours aren't accurate and valuable. But it's taking us some energy to sort through them.