People say 2 ohm has better Sq, but unless you have Superman hearing abilities you won't be able to tell the difference. I also ran 4 Type R's in the past with 750rms a piece. If you feel like 500 a piece is enough, then get the Alpine. I'm not saying the other amps are better, they just are more power than Alpine for the same price. You can always turn the gain down. I'm not trying to sound like a hater, but those R's don't have the best Sq. I say that because you seem to be worried about Sq? The amps I suggested are pretty good even compared to Alpine. Don't get caught up in matching name brands. There's a guy on youtube running an Aq3500d on 4 Type R 10's.
The Autotek is 2 2000 watt amps strapped together in one case, I think? That's why it is 2 ohm stable. Yes, that's the right model number for the Dtr. Let me know how the Alpine turns out because I already know that's what you're getting?