I have the Alpine IVA-D900 head unit now. I just ordered an AVIC D3. I'm not to most electically savoy person, so my question is should I just resort to a shop or is the cross over simple enough that I can do it myself? I'm also going to install the XM radio, bluetooth and Ipod adaptors to the system at the same time. Any little bit of advice would be great. Thanks in advance.