2 or 4 ohms?

I have a KAC-929 Amp and want to put in a couple of subs. The amp is suppose to be able to push 230x2 RMS at 2 ohms. Or 150x2 at 4 ohms. Now I will be purchasing 2 12's and am trying to figure out the difference with the ohms. Is it better to run it at 2 or 4 ohms. Im assuming 2 ohms would be better. Now will the sub be the only factor in deciding the ohm load with that amp? Do I have to specifically purchase 2 ohm subs?

Not at all. You can purchase 2-4 ohm subs, and wire them in parallel to get a 2 ohm load. You can get a single DVC (4+4) ohm sub, and get 2 ohms, you can get like 4-8 ohm subs and get a 2 ohm load ( i wouldnt do it, but its possible). However, for most power to each sud, i'd get 2-2 ohm subs. 230 watts isnt much to be splitting to a bunch of subs. So, you're best bet would be to get some 2 ohm subs. Question, i see that its a 2 channel amp. Can that amp be bridged? If so, you could get a pretty nice sub, and run it at 4 ohms bridged to get some more power outta that thing. 1990 Honda Civic HB:

Clarion DXZ545MP H.U.

2- 6.5" Power Acoustik interiors

Diamond Audio 600.1 amp

Diamond Audio 15" M6MKII

Pyramid PB881X 4 CH. Amp

well rob, assuming his amp IS bridgeable, wouldnt you recommend he went with a 4 ohm load? I know I would. It would probably have the same output as the 2-2ohm channels (230+230), but in 4 ohms which would be a little cleaner. 1990 Honda Civic HB:

Clarion DXZ545MP H.U.

2- 6.5" Power Acoustik interiors

Diamond Audio 600.1 amp

Diamond Audio 15" M6MKII

Pyramid PB881X 4 CH. Amp

It is bridgeable. It runs 230x2 RMS @ 2 ohms and 150x2 @ 4 ohms.

So according to that wiring diagram I run it in a bridged form and split both the positive and the negative and run them to the one terminal on each sub. Then I connect the other voice coil on each sub from positive to negative?

2 ohm stereo should produce the same thd as 4 ohm mono, shouldnt it. Just because the impedence is lower doesnt automatically mean its gonna drop the sq. If im not mistaken, which I may very well be, does the thd not go up because of the increased load and the subsequential heat the amp produces. If thats the case than the difference between 2 ohm stereo and 4 ohm mono should be the same thing since the amp see's both loads as the same thing.double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer