Ya, the 225 is for 1 pair. You can run them off a deck or an amp, but if you are going to run it off your deck, I suggest running new speaker line from the deck and mounting the crossovers in the car. Just ask if you have any other questions. (I can intall them as well if needed)
Ok, ive had a few questions about the quality of these speaker, mainly do to the fact that many people have not heard of them. The reason is because they are not widely available in Canada. The are a high end speaker similar in quality to Focal, Rainbow and Dynaudio. Maybe you havent heard of those either, but they are good.
Here is a link to the CDT audio page that contains magazine reviews in it: