I agree (not about the tata's). I see all these systems these days talking about 1,000 watts this and 5 cubic foot boxes and then it doesn't do anything. OP, I am by no means trying to get down on your system, this has been building inside me for a while and I gotta comment.
I just walked out and did this. Here's 2 tens on 99 watts:
YouTube - 2 tens on 99 watts
Here's the system:
YouTube - new amps
The box is .64 cubic foot per sub, that's just at half a cubic foot for each sub, I get to keep almost my entire trunk, I'm running a whopping 99 watts of power to the subs (44 watts each).
I drive a Lexus which has a steel back wall and NO PORT THROUGH. As juvenile as this window trick stuff is (I mean c'mon I'm 33 and been doing this 15 years) I did it to show that it doesn't take much to shake a pillowcase.
If I had a 5 cubic foot box and 12's on ANY amount of power I'd be pissed if I couldn't make that cloth stand up on that window. You should probably tune up a little by shaving that down down some. The frequency you are at doesn't agree with those subs.