Price and loudness. The fact that I own a convertible opens me to two situations....wind/road noise and theft. SQ is pretty much out of the question when you don't have a solid roof....so my main concern was to actually hear my bass considering the increased amounts of wind and road noise in a convertible. Not to mention the ease of everything being stolen. I put my entire system together, including materials, for under $800...so it's not gonna break the bank if something gets stolen. And not to toot my own horn, but it actually sounds better than some system's I've heard which have cost in excess of 3 times that amount. You're welcome to take a listen some time. Not to mention my system is about 3 years old....I do so many systems each week, I don't even have the desire to fuck with my own.