thanks for everyones interests.
i have decided that it would be best if i didnt sell the setup. i can just move it into another vehicle as a trunk setup.
the reason for this decision is based on a few variables that might upset someone with an ST that i dont feel i can explain fair enough. one is that although the seats go up fine, you MIGHT have to extend the locking bracket just below the rear window by using some washers and nut. I completely forgot that i had to do this when i installed the box. the seat will lock correctly with the bracket extended by 1/4 " or less. some might feel that is a safety issue, i do not. The seat is not anymore upright than normal.
the other issues are that the entire trim and plastic behind the seat needs to be removed for the box to sit in that well. it is a very tight fit, im not comfortable with the thought that this box might not fit because the metal lip on the next guys st is bent in just 1/8th of an inch.
and finally, the issue described in my original post, if you like pounding bass, this box, speaker and amp will definitely do it, however you will probably want to lower the 40% half seat so its not muffled. regular music listening does not require this.
I am a very honest seller and these issues were not explained to me when i bought the box, but id feel really bad if someone did not get what they were expecting in any respect. i was going to video the subs playing music and the amp to show anyone that was interested but as i mentioned at the beginning of this post i think im better off just using this in another of my vehicles. thanks for your interest