Got a good deal on two 12" subs. Help w/amp?

Today I picked up two 12" Audiobahn subs in a ported MTX box for $20, lol. I did a little research and from what I gather I got a couple decent entry level subs for next to nothing. They appear to be in great shape, but I don't have an amp to test them out as of yet. I am now on the lookout for a used amp, of which there are plenty in the classifieds here in the Salt Lake area.

In my wagon I have a Kenwood KDC-252U, 50w x 4 HU, two 6.5 Pioneer coaxials, and two stockers in the back door panels. I have already installed all the necessary wiring for an amp and subs in the back.

The Audiobahn AW1251T subs I picked up have the following specs:

• Sensitivity: 92.1 dB
  
• RMS Power Range : 400 Watts
  
• Peak Power Handling: 800 Watts
  
• Impedance: 4 Ohm
  
• Low Frequency response: 24 Hz
  
• High Frequency Response: 1000 Hz
  
• Diameter: 12 Inch
  
• Number of Voice Coils: Dual
  
• Hella Dope Chrome Flames, Holmes
  

I know absolutely nothing about amps. What is the minimum wattage amp that I need to power these subs?

Also, the box that the subs came in is an MTX box. It also has two Motorola Powerline tweeters installed. Any tips on how to wire up the tweeters and/or do I wire them up to the amp that powers the subs?