ebay sounddeadening is fine. put multiple layers closer to the drivers and then spread it out. 20% coverage gives 80% effectiveness so dont be too crazy.
Replace the fronts with components (tweeter seperate)and put in lower mid/bass drivers in the parcel shelf. (or get a set of three way and disconnect the tweeter array) This prevents your stage being drawn back behind your ears and gives a much better soundfield experience.
Amp the fronts, the rear 'could' be run off a headunit if budget is a consideration.
Sub in the boot, tie it down. play with the knobs till you like how it sounds. If you can get a headunit with crossover function even better. I hate how the mids try to play down to the bass notes when they have no business doing so. If you can cut those frequencies from the signal they will work much harder where you want them to.
I am sure ratty will come in with some more soon as he wakes up

6th gen Prelude please Mr Honda. RWD 2.4 turbo lude.