If you can post a link to the manufacturer's webpage for the specific model or give me the exact model name/# of the sub, I can help you figure out what you need. If you don't know what it is specifically, search around the manufacturer's website until you find out what the model is. Maybe post a picture for us, too.
I'm assuming the 300w is max power...you really need to find out the rms power rating. That is more important for matching the subs to a correct amp.
But, if it is 300w rms then you would want a 600w rms amp since there are 2 subs (300 x 2). If that makes sense. Try to match the combined rms wattage of the subs with the rms wattage of the amp. Likewise, try to match the combined max wattage of the subs with the max power of the amp. The rms rating is much more important to be matched, so look for this match before narrowing the list down using the max wattage.
And like I said earlier, I'd recommend a monoblock or 2 channel amp for this application. And try to get an amp with a signal to noise ratio like 85db or better. Also, try to get an amp with the thd% below 0.05%. Finally, you need to determine how many ohms the system will be running at and if your subs are single or dual voicecoil. Check out crutchfield's wiring diagrams for the different possible setups. You need to know the ratings of the subs first, then find an amp that can work at that level. Since you are running two subs to one amp, it can get a little confusing. For instance, if you run 2 4 ohm single-voicecoil subs to a monoblock amp, you will need an amp that can handle 2 ohms I believe. So I guess the first step is to just figure out the exact specs of your subs and get back to us. Hope that helps.