Help with Alpine 12 type R

Ok I'm Looking to upgrade the subs in my truck from 2 10" bostons to 1 12" alpine type R.  Now my question is should I get the dual 4 ohm VC and run it at 2 ohms, or should I get the dual 2 ohm and run it at 1 ohm or 4 ohm. What way would be better. and what amp would you suggest to power it, I was thinking the MRD-501. I see on alpines site that they say its ok to hook up 2 amps to one sub, I thought that was a big no no. But if that is true would I be safe hooking up my Eclipse EA3422 amp that was given to me for free, basically brand new(its still under warrenty),  Could I put that amp in 2 channel bridged mono and put 140 Watts RMS to each voice coil. Any and all advice would be helpful

Thanks,

basically just look for an amp in the 500 wrms range, ,then , match the sub to the impedance that the amp is capable of.

Like a mrd-m501 is capable of a 2 ohm load, , so out would get the dual 4 ohm sub.     If you get a 2 channel amp that bridges at 4 ohm, , then get the dual 2 ohm sub.

I second this... I have a mrd-m500 power 1 12" type R Dual 4 ohm... In a 1.25 cubic foot sealed box (recomended by Alpine Guy) And it sounds awesome... way better than I ever expected it to

sorry it took me soo long to reply, I have been so busy and driving 700 miles in one day round trip to pick up stuff. I was thinking one 12" type R dual 2 ohm VC in the vented box, that unit can't remember the model number, with the MRD-M501 amp. How do you think this would sound, It will just be sitting on my back seat of the truck.

Thanks,