Installing HK traffic Pro in W210

I brought a HK traffic pro and I am about to install it. I understand it is an easy install. However, I welcome any comments and installation tips.

I intend to place the antenna between the two defrost vents at the base of the windshield. Can I pass down the wire down through the duct into the radio opening without much fuss??

I also intend to take down the CD changer and replace it with an MP3 source. Should I go with either:
1.) an iPod or any DMP with capacity > 5GB or
2.) an in-boot MP3 changer with suitable adapter if there is any.

All suggestions and help greatfully welcomed
PA2TU