My review of the TRD Door stabilizers...
Picked these up in Japan for a decent price. Just installed them a week ago. Initial impressions...
On installation... Fast and easy. 15-30min job depending how many pictures you wanna take of the process. Lol. The stock door latch screws were no problem to remove with just a socket wrench. I wouldn't want to try to loosen it with just a screwdriver though. No impact tools needed. I mean, if you're weak, then I guess a socket wrench might not be enough. But my socket wrench I used was only maybe 4-5". Not much leverage at all. Not sure why some people have harder time than others removing the stock patch screws. And yes, mine were covered in blue loctite.
Maybe all our crappy Hawaii roads jostled and vibrated my screws looser than normal. Haha. Install is pretty straight forward. Just be sure the door closes nicely before you tighten down the door latch completely.
Door closing... slightly lower in tone but barely noticeable. And by barely I mean I could only really tell the difference after installation on the first door by opening and closing the stabilized and unstabilized doors one after the other. The 'thunk' feels firmer as expected since there's extra metal and plastic wedged between the door and body now. As far as amount of force used to close the door, I haven't had it bounce back out on me unless very very gently intently closing the door, which is almost never. Mid-install I took a vid of opening and closing the stabilized side vs unstabilized side and advancing the video slowly I can see the unstabilized door bounces back and forth on the top by the window vs the stabilized door not doing that. Basically there's a firmer fit between door and car now.
Dive feel... Definitely better. FYI, I'm on stock suspension. Taking my driving mods slow here, wheels and tires were approx 5 months ago. Not sure how this change feels on a car with modded suspension bits. From the first drive, the car feels tighter. I'm talking about driving on the twisties here. Tight, hard, and fast turns. Tantalus and Round Top drive for you folks that know Oahu/Hawaii. The steering is more responsive to my inputs. Like there's less slop in the back end. Like the front and back of the car are more connected. Like the front and back move as a whole now instead of two separated pieces. I thought the steering response in this car was good before, it's better now.
In normal granny driving on regular roads and on the freeway I don't really notice a difference. And I don't have a track or wide sweeping turns to test this out on like people in more open areas on the mainland do.
The difference is in the winding twisty touge roads. (Side note: is there an English word for touge? Mountain pass doesn't seem to be the right word, and it's not canyon driving, mountain roads maybe?? I'll just call them twisties). Anyway, it's not a placebo effect as I know those twisty roads well and have to drive them in the dark even (middle of the night/early mornings with no sunlight and no street lamp posts around) where you'll need to trust your muscle memory more than your eyes, to take the turn at speed. Depending on work, I'm driving these roads 3-5x per week, 2-5 passes a day, so I know how my car feels on every turn of those roads. I noticed my steering inputs are different now to take the turn the way I normally want to. Different enough where I won't take the turns at my normal speeds in the dark until I get used to the new feel. And in case anyone asks, my tire pressures are fine.
Overall impression... Do you take your car to the limit on the twisties? If so, then this mod may be worth it to you. It's worth it to me and cheap enough where even if it did nothing, it's an extra shiny bling that says TRD on the BRZ. Haha. If you only drive like a granny and/or never on twisty roads, then money may be better spent elsewhere for your needs.
TL;DR - Car drives better on the sharp, tight, fast turns in the mountain twisties... And no real change in normal granny driving.