on my sundown sa 8 v.2 the dust cap gets really hot? is this caused by the voice coil being hot also why does it tend to clip (bottom out) when its straight up more then it does down or at a 45 degree angle? i have this in a .28 cubic foot sealed box in a apk 2500 watt amp and i cant figure out how to get it to sound crisp and clean

Having heat on the cap is a result of the coil be far to hot. There is only a few things that will cause heat, one being clipping the signal, the other would be improper enclosure, the other is just to much actual power.

You answered one question already...

How do you get it to sound crisp and clean?

Well, going over xmax sure isn't the correct method and running a 2500w amp on a 500w sub isn't ideal for crisp and clean either.

Sub is getting hot because you have too much power.

Sure, i run 7x the power to my subs but it's not sustainable. That's why i turn it down for longer runs.

I think you got your answers.

thx guys!!!

i guess my real question is why does it seem that i cant get it to sound good unless i have the gain at 3/4

I'm not sure but I would venture to guess that the v2 like the v1,v1.5 doesn't do very well in a sealed enclosure. You're simply asking more from it than it's capable of giving with how you're trying to use it. Build a good .6cuft ported enclosure for it with a good amount of port area and I'll bet you'll get much better results.

Speakerz iz dum, dey only do whut u tell 'em to do.

You also have to realize, it's not a 15, not a 12, not even a 10. You're simply expecting wayyy more from it than it's capable of doing, especially with the enclosure it's in IMHO.