You can still do this, but it will be hard to find 6X9 woofers. Very few companies make them any more, if at all.Just as a side note how old was this 'stereo tech'? The way the system in an Accord is set up is that the front door and rear deck speakers are full range single drivers and they added tweeters in the dash that have a simple 1st order capacitor crossover on them. That's it, nothing special. There also is no amp, it's just the stock radio's power output that is being used.Don't worry about showing your age, I can remember building systems like that many times over. I think that adding a 5-channel amp may be a bit overkill for what you want to acheive. Possible pulling the rear speakers and putting in an amp with a small sub on it would be a much better solution. this will add in the low end that you are now missing and will also remove some of the extra mids and highs you have gained by putting a 3-way speaker behind you. I've never understood ading mids and highs from the rear in stereo applications music is designed to be heard from in front of you. All adding speaker to the rear does is drag the imaging back and mess it up.
