The BOSE amp in my car has just been repaired due to water damage, it was damaged when I bought the car so this is the first time I've been able to listen to the stereo with the amp installed and working (yes I fixed the water leak first). I've noticed it doesn't take much bass at all to overwhelm the speakers, hard to explain but when a speaker is given too much bass it makes that unmistakable flappy flat sound. I've tried fading and balancing the sound just to see if any one speaker is worse but I can't really pinpoint it so I assume they all sound a bit dodgy when any bass is applied. Currently all the equaliser settings are set at the default (12o'clock) position and if I turn the bass up much more than that it does not sound that great at all. I currently have some 320kbps mp3's on the SD card so I'll try some proper CD's over the next few days as well. A mate of mines Bang an Olufsen in his similar age A5 sounds much much better and handles bass brilliantly, I guess that's because he has a factory sub in there somewhere and as far as I can see the TTS does not have a sub. But still, I would have thought I should have been able to get bass that doesn't sound all distorted and flat. Could I replace the main door speakers and the speakers in the rear for aftermarket and keep the factory tweeters in the dash? Would that help?