Trying to pick the right amp to go with 2 10" Fosgate Type 2 subs 200 RMS @4ohm, 400 max. Plan to wire them in parallel for 2 ohm load. Mono or two channel amp?, exactly 200 RMS amp or do I fudge up a little? Do I divide amp wattage by 2 if using 2 subs? Looking at SPL CRM8202 (2X230 RMS @ 2ohm) am I barking up wrong tree?
two subs rated 200 wrms = 400 wrms power needed. no matter what speaker load you end up with, you are looking for 400 watts total. you can power the subs separately (stereo) or wired together (mono).
if mono (the preferred method, IMO):
the 2 ohm load (two 2 ohm subs, parallel wired) will require an amp that is stable into 2 ohms mono. this is important. you'll probably want a single-channel amp that's stable into 2 ohms. this amp should be rated for 400 watts into 2 ohms. it may say 200 watts into 4 ohms, but that's okay as long as it gives you what you need at 2 ohms. i would not try bridging a 2-channel amp to power a 2 ohm load unless you know what you're doing.
if stereo:
driving each sub separately (2-channels) means you're not creating a single 2 ohm load anymore, but running dual 4 ohm loads instead.
the CRM8202 you've mentioned supplies 230 watts into 2 ohms, but it will only make half that into 4 ohms (that's just the way it works), so it would only send 115 watts to each sub. to do the stereo set-up correctly, you'd need to use a 2-channel stereo amp rated at 200 watts per channel into 4 ohms.
to simplify things, JL audio makes mono amps that put out the same amount of power into various loads (2, 3, 4 ohms, etc.), so they can handle most any thing you throw at them. might look into those if you can't find an amp to exactly fit your set-up. good luck.