Hi guys

Have participated in a few thread discussions re stereo upgrades as well as reading back and am still not sure on this one.
What is the difference between the facelift stereo systems in terms of quality?
The reason I ask is my Omega has the standard CDC2006 4-disc head unit. To me ears this sounds vastly superior to any factory fit unit I have heard before - especially in terms of bass reproduction. I do not yet know if the speakers are stock or have at some point been upgraded, but they do sound pretty nice, lacking id midrange though.
Obviously the standard units complement the interior and work perfectly with the wheel controls & GID so I am not keen to change without a good reason. So - what would the options be with regards upgrading to a Bose setup? I have read previously this is not compatible with the 2006 head unit, not sure what it does work with?
Would this be a better option than splicing in a small active sub and if necessary upgrading the speakers? Have an old 200w Pioneer tube knocking about which needs a home. I figure it is probably only worth upgrading the head unit when the budget allows for a fancy 7" screen integrated satnav which is what I really want.
Does the Bose offer such a massive increase in sound quality that it is worth the hassle (and if so anyone got one for sale

)? How much of a job is it to splice in to the car (2000 saloon)?
At the moment my initial plan is to bung a set of 6.5" JBL speakers which I already have into the front doors, connect the sub and see how it sounds (unless I find something better in the doors).
Some advice would be much appreciated before I start - just how do the standard Vauxhall setups compare to (modest) aftermarket replacements? The 2006 heads seem to change hands for insane amounts of money on ebay...
Really sorry for all the questions - hope I make sense!
