Based on my current setup, this was the reply I got from TIF2 when I asked about the best way for me to go for a lid solution...
The non-Ultra overlay harness already has connectors that will plug into the harness that is provided as part of the rear saddlebag speaker lid kit. You will need to get the 2-ohm version to attach directly to the Harmon head unit. Then, you will need to get the radio flashed to enable rear fader control (that, as well as a "special qualization" flash) is included as part of the rear speaker kit. However, some dealers will charge labor to install the included software.
The problem will be output when driven only by the head unit. You'll probably be disappointed. Hogtunes has a pretty cool bracket to mount their new 70.2 amp on the right side of the inner fairing - so you could add that amp to your exisitng system pretty easily. This amp would only drive the rear lid speakers, leaving everything else about your present system intact.
Of course, if you wanted to start over with a 4-channel amp then the sky is the limit 
I haven;t checked all the colors available in the factory painted speaker lids (I'm surprised Spiced Rum isn't avail?) but Paint by Gene has done Spiced Rum before. They are located in Seattle, WA.
Hope this helps ...
[/size]
Currently I have:
Hawg Wired DCS1202 DCS Series 120W Amplifier
Hawg Wired SX Series 4 Ohm Component Speakers
Hawg Wired STK100B Dash Tweeter Kit (Gloss Black)
Boom! Audio XM Satellite Radio Kit - (76404-06)
Overlay Harness – Non Ultra - (70169-06)
Harman/Kardon Dummy Module
Now I will be ordering the 2 lids in primer (90200612, 90200613), and the "Boom! Audio Saddlebag Speaker kit" (76000202). I will add the Hogtunes NCA 70.2 amp using their mounting kit (4405-0234) which allows the 2nd amp to be mounted the radio and the brake side speaker.
My only hold up now is my brain. I need to understand how this all gets wired. I have read the instructions and from what I can see it will be almost a "plug 'n play" deal under the fairing but I'd like some confirming opinions. I'm also wondering how to wire the speakers given the bags have to remain removable. Does the wiring in the Boom kit cover this?
I almost have clarity on this... Just need that final bit of fog lifted.