wrx seat mod you should find some threads about it. I think this was the thread that I saw.
What I did:
1) find the zipper to the seat. I reached in with my fingers and pulled out where the zipper starts
2) unzip and unhinged the bottom part of the flap.
3) As you can see from the first image above of the bolster has 3 hooks on each side that hold it on to the seat. The top two are really easy to get undone.
4) The bottom on I used a pliers and grabbed on the black piece and lifted up till it came out. (you can see the piece I grabbed on in the first image on the bottom left)
5) Slid the whole bolster out. No need to really rip any of the plastic.