Thank for tip.
I'm kind want remove it out this week but I'm working lol. I plan remove pass seat only so I can drive to this guy's area this Sunday to put pass seat (not install.. just put it look like that lol) then install back seat and beach seat. Then put driver seat on my backseat. 4 doors panels on my trunk which it should be fit.
Mostly, I'm worry about door panels. I know they are easy break. I hope this guy didn't break it when he will remove that door panels. I already told him be careful. Pull it up first when you removed 2 plastic tabs.
for backseat write-up
beach seat (easy as hell) just pull it up that it will snap it off where 2 holes on frame.
the back seat actually have 2 black bolts then lift it up from 3 tabs then pull it out. Maybe GT/GTP might have 4 bolts since my car is SE model. We might have different tool or whatever.