this is a good question.
a friend of ours drives a BMW 7 series. its basically a garage queen but he and his wife brought it down to Miami for a function. on their trip home a cop pulled them over for no infraction but to do an inspection on the car stating they were aware of drug traffickers. he of course let them inspect the car because he does not do nor sell drugs of any kind.
after they returned home he contacted an attorney friend who told him he should have refused the search of his car. i can't remember the details as to why or what right he had, but he did have a right to do so.
so if anyone can chime in on this it would be apprecaited and i'll try to find out more about what he was told when i see him next.
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if you can only race me in a straight line then whats the point 
...91 SMF SCCA
http://www.flickr.com/photos/8341770@N07/5601083432/http://www.flickr.com/photos/8341770@N07/5601083432/ by http://www.flickr.com/people/8341770@N07/, on Flickr
I see people out there spending money on the car to improve it … If you spend half that effort just working on your driving skills, making you and the car work together as a team, then you’ll go faster – period. To make the car go a second faster on the track takes a lot more energy and money than making yourself drive it one second faster.
– the late Tom Thrash SCCA Solo E Production