It depends! I have seen where a trunk has actually made it sound better. Everything depends on placement inside the trunk, type of box, subs, amps etc. Honestly nothing sounds better than some house music played on a sealed enclosure housing a set of 15's, box all the way to the rear, subs facing trunk lid. Dynamat will help the lid rattle.. Polo.
It's obviously not as loud since the trunk is separated from the cabin. It also causes a lot more rattling (the trunk lid).
Something to think about, on a lot of cars you can remove the rear deck, or if your rear speakers are there, just remove those since there's really no point to rear speakers......
im not sure exactly what your asking, but goin by what i think, no, the grille won't make a difference really if it stays on w/o the speaker in place. but in some cases the grille mounts on the speaker
yea im cuttin into the back of mine to just to let some air flow to cabin a slot hole cuttin into seats to match then coverin it wit w/e i feel like at the time and no to dynamat Joshua Moye
your trunk will rattle badly but inside the car it sounds great. especially when theyre facing the back of the car (not towards your seat). outside the trunk will rattle lots (mines horrible dont know abuot yours) but outside from aways away or with your door open itll still be as loud. run some wires back to your trunk and test it first without hiding the wires. oyeah and if you have the seat down it will sound about the same, maybe better because the bassline has more time to develop.