I have 1 10" ported powered by 225 watts at 4 ohms.

This 10" subwoofer is built with quality. It has W7 patents which shows as soon as you look at it up close. The output this subwoofer produces off 200 watts vented is surprising. The subwoofer looks like it can take a lot of power because its built so tough. If you have a hatchback car this thing will surely satisfy your bass appetite. If you have any other car and just want to fix a low frequency output gap then this is good. If you want to really get loud then having multiple of these is undoubtedly necessary.