How to wire a 2 or 4 ohm subwoofer question?

Question

Im thinking of getting an amp the pushes 900 watts at 2 ohms(its mono)... and the sub im thinking of getting comes in 2ohm and 4 ohm...so if i got the 2ohm sub all i would have to do is connect each thing to there thing on the amp right since there is four?and that would give me a 2 ohm resistance right? And what would i have to do to drop 4 ohm to a 2 ohm... here is the link to the amp and sub...

amp

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=350068333774

sub

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=270244549515

Answer 1

You are correct. A 2 ohm  speaker could be hooked up directly to the amp that is designed for 2 ohm. If you had two 4 ohm speakers hooked up in parallel that would give 2 ohms of resistance. But if your only getting one sub, get the 2 ohm.