What is the best after market GPS Navigation system for a 20

What is the best after market GPS Navigation system for a 2005 BMW 545i? Alpine? Garmin?
Also, when you mount it, if it's mounted on the windshield, does it shake when you drive? If you mount it on the dashboard, do you must permanently stick something on the real dashboard itself?

I'd go with Garmin..Garmin is widely used in Aviation.Lots of big Jets use Garmin for navigational reasons. Same maker, but different kind of navigation. If Pilots use it, then it must be good.

Garmin are now the best in the market, they have so many models to decide from that suites your needs, check out there web site.
They have alternatives on where you want to mount it, and once done, it doesn't shake, and no you do not have to permanently stick anything on the dash board.
Hope this helps

I has been impressed with Magellen the most.
It comes down to personal taste, and what you need it to do.
I travel lots, and like this brand.

I recently got a Navigon 7200 and love it....blue tooth, zagat, a few million poi. check it out. we got ours at costco and are very happy. ......good luck with your search.