If you're trying to squeeze every inch then, yeah the 3000Micro is a great little sub. However, if you have a little bit more room I agree with soix's recommendation of the SB1000pro. It'll best either of your choices.
I had a pair of the 3000's in a 11.5 x 14 room and after some tweaking I was very happy with what they added. Depending on your room size they won't dive deep below 30hz but that's where the SB1000 will work better.