2004 325i Question on adding GPS Navigation

Hi there,

I purchased brand new 2004 325i w/premium and sports pacakages on ealier this year. Yes, xenon also.
I am loving it so far, its handling, stylish, etc. However, now I regret not getting the navigation system. For the price of the car, my car lacks of little fun toys to play around with. After a while, it gets boring.
I see that, although I don't have the GPS navigation system nor the display, there is that shark tale antenna on the roof. Is there any way I can incorporate this antenna to add gps navigation? How do I go about finding and installing gps navigation (of course, display too)?
Any suggestions? getting cheaper after market bmw gps systems plus display? or other brand? Where to buy and/or install?

Your input is most appreciated!!!

Thanks in advance for your interest.

You have a few choices, you could go with the Pioneer AVIC series DVD players with builtin navigation for about 1300$.

Or I believe Bavarian Autosport sells a smaller edition, without a GUI for about 500$ (www.bavauto.com)

There are also handheld models like Magellin and what not.

The choice is really up to you.