Should be loud, but will not be the prettiest sounding thing you have ever heard (although it really won't sound "bad").
Looks good to me for a first setup....but you may want to look around a little more first. I would recommend, if you have the depth, looking at a single 15A (
http://www.edesignaudio.com) and any amp that puts out between 800-1400watts RMS....I will be powering mine with a crossfire-1000d (1000-1200watts at 1ohm)
You could also look into a pair of Re SE's, or ed K's, maybe a single brahama (sp?)....or if you would like to save money, pick up some pioneer premiers on
ebay. All of these subs should do very well depending on what you are looking for....
The k's are 50/50 spl/sq, Se's are more spl (but will still sound clean), brahama will get really loud and have great sq, same with the A, and the pioneers may lack in output, but have pretty good sq.
To see where the hx2's fit in, they would be quite loud, but not have the sq of any of the subs listed above.....tell us what you're looking for and we may be able to help better