Before I had the BOSE sub fitted, I found the sound was good using the following settings:
EQ - ROCK - LOUDNESS ON - BASS +6 TREBLE +6
You could only turn it up to 35 though before destortion kicked in but for me this was loud enough. The door panels did rattle somewhat though!
I beleive that models with velour/cloth interior (I have velour) have better sound becuase the material is softer and more absorbant than leather.
Since having the BOSE sub fitted, I am now able to take the load off the door speakers by having the following settings (yet still gaining a significant increase in tight bass):
EQ - ROCK - LOUDNESS ON - BASS 0 - TREBLE 0
Here is my thread about retro fitting the BOSE sub - its not cheap though but its fairly easy to source the parts and does a really decent job especially given its compactness -
Yes those speaker connectors on ebay were the ones I was going to suggest. Should make the job a lot easier for you! I'm guessing you have new door plugs for the interior door panels to fit and I'm assuming your drilling the centre of them to extract them as apposed to prising them out with a screwdriver and chewing up the plastic!
On a seperate note, I borrowed Garry's GT Cloverleaf from Alfa Sport the other day for a couple of days and this was the first car I have tested with BOSE. Interestingly, I found that BOSE set the amp up so there is more volume on the left speakers than the right due to the fact that your closer to the right speakers! For me though, it was OK, but not worth the £650!