I really think you have enough power. The 800 is the rms right not max? If you want cleaner bass might want to look at getting a new pair of speakers. If you just want louder bass id say ported only problem is the box would probably be huge for two 15's ported. I would not suggest just throwing them in any box. It needs to be built just for your speakers and ported boxes are very finicky about measurements that are off. Sealed you can be off a fair amount before it affects anything but ported has to be basically dead on. My suggestion is try ported first then if you still don't like it look for new subs. One of my old friends had two xlc 10s off an mtx in his ranger and is was pretty loud i used an xlc 10 in my ht for a while and had it for a bit in my car. Probably not the cleanst though. The only other thing i can think of is that maybe your speakers are not wired to get the most out of the amp. How many ohms are the subs and how is it wired together?