X5 Radio questions

[amentges]

A few questions on my radio, I have a 01 X5 3.0 with premium sound, dsp, no nav, and tape deck. The things i would like to accomplish. Remove the tape deck and put in a cd player (i have a changer but just hate the fact that any car company past 1995 would still put a tape deck in) and replace the headunit so that i can have the aux output for sirius or an ipod. Questions. Can someone point me in a direction to where i could purchase these things. Also i believe i need to converty from the round plugs to the flat ones? I guess i need to know where to get this converter? Also how difficult of a project this would be or if it were better if i just took it to the dealer with the parts and trie dto get them to install it? Also if i do upgrade the headunit will i be able to control the sirius or ipod via the steering wheel controls? Thanks for the help.
Andy