What type of amp will be best for two of these subs?

Class D mono w/o question.

For high power apps like this they're about the only way to go. It would be a rare exception these days to go any other route.

You also need to consider your electrical system. 2kw is too much for any stock alternator, especially in the long term.

If you want to find a reasonably priced amp you might want to go with the cwr154's instead. That will give you a 1 ohm wiring option which is where the majority of the big power sub amps will work best.

Not sure what you're looking to spend, but here are a few worth looking at:

http://www.soundqubed.com/Q1-2200D_p_31.html

http://www.sonicelectronix.com/item_43838_Precisio...

http://www.sonicelectronix.com/item_44471_MB-Quart...

http://www.sonicelectronix.com/item_68123_RE-Audio...