Mazda3 S, Whats it worth?

Hey I have a 2004 Mazda3 S, with leather, Sport package, Xenon, Tire Pressure gauge, basic everthing but 6disc, sunroof and navi, I have tinted the window, and put in a JL box and sub and amp, with seperate bass control, my question is what is a good price to sell it for? I know I have had the car for all but 1 and 1/2 months, but I have a plan, and I need to sell the 3 and Kelly dosen't have a blue book, so let me know what you guys think is a good used price to sell it for.
shag'(evil)

Most people would say less 3G from the time you've purchased and I hope you did enjoy your wagon.

all your posts now u wanna sell it.........(scratch)

only to step up to a rx-8, thats all, if i do sell it, it would only be for an rx-8, otherwise i'm keeping it