I have not had one on my 325ci since I bought it back in 2001. I have lived in houston and dallas areas and have driven to austin probably 50+ times and no ticket. I was only stopped once by a cop that was standing by his bike at a school zone. He stopped me at a stop sign and told me I needed to put one on or I could get a ticket... Trust me you wont have a problem unless you get a cop that just wants to be an ass.
2008 M3 Space Gray, Black, Syc Ant Wood Trim, DCT
2001 325ci Steel Gray - Sold