If you are dead set on getting a single 200W speaker, go with this one from FedSig.
http://www.fedsig.com/products/index.php?id=120
Do NOT get the one from SpeedTech. Their products from what I understand are not well built and they have a high fail rate. I think you will come to find that other members will tell you the same thing. It is always better to get a brand name product over a knock off. The big brands will also be there in a few years for warranty purposes and they are usually much better built, thus last longer and perform better.
I would still personally go with a pair of 100W speakers. They are cheaper and easier to replace should something fail. Also, if you have a single speaker and something goes wrong you are out of code capabilities, where if one speaker in a dual speaker setup fails, you still have one speaker functioning for responding purposes.
You may also consider, depending on what your purpose for the speaker is, that 100W is plenty for most
POV and many official vehicles. So ask yourself do you really NEED (not want) 200W of sound or will 100W get the job done fine and save me $120+ to keep in my pocket or to put toward something else.
Hope this helps. Let me know if you have any questions.