From all these replies and talking to a local shop I think I will bag the "lid" idea as I only ride alone and am looking for sound at speed.
Sea Biscuit, you are saying that there is a huge difference with changing the speakers and amp in the front but keeping the same stock look?
This might be a dumb question but are those components meant for a bike?
Huge difference going from the stock Boom Audio to what I have now. So much louder and clearer (I don't have to "guess" what is now playing on my sound system at half the volume). I mostly use my iPod and record uncompressed and it is quite impressive on how loud and clear this system actually is. If you are mostly listening to CD's or iPod, the HK head unit works quite well with my setup (I actually was thinking about changing it but the shop that I was/am still working with talked me out of it).
I have no illusion that the bag speakers will be as loud at speed (yes officer, I obey all speed limits

) as my front setup, but with my 6X9 Focals in the rear, they should provide good "fill" when travelling.
My Arc Audio amp is specifically made for motorcycles. The Focal speakers are not specifically made for motorcycles but the shop that did the install uses them quite a bit in motorcycle applications and hasn't had a problem. I've washed the bike a few times and the speakers got wet but no problem (although I wouldn't put a high pressure hose to it,,,they look to nice to do that

)
FYI, the shop that has done all my CVO paint (lids and Razor-Pak) is
http://www.gcpaint.com/. They do the CVO paint for Harley and match paint and graphics perfectly. Talk to Kent.
The shop that I am working with on my stereo is
http://soundzcustomz.com/. Talk to Pete.
All I can say is the Arc Amp and Focal Speakers "rock" with the stock HK unit and you will not be disappointed with spending that money on the upgrade when you are rolling down the highway jamming to tunes with a big

on your face!