Installing a 4th brake light brz kit is basically a rite of passage if you've recently picked up Subaru's lightweight coupe. It's one of those mods that almost everyone does within the first few months of ownership, mostly because the factory setup feels like it's missing something. If you look at the rear of a stock BRZ, there's that little triangular plastic piece right in the center of the rear diffuser. From the factory, it's usually just a dead reflector or a blank plastic plug, and honestly, it looks a bit unfinished once you notice it.
The car has such a great silhouette, but that empty spot at the bottom always feels like a missed opportunity for some extra flair. When you swap in an actual functioning light, it transforms the rear end of the car, giving it a much more aggressive, "complete" look that Subaru probably should have included from the factory. Plus, it's not just about looks; there's a genuine safety benefit to having an extra light down low, especially on a car as short as the BRZ.
Why Subaru Left a Hole There
It's always been a bit of a mystery why car manufacturers leave these blank spots. In some markets, like Europe or Japan, that lower light is actually functional as a rear fog light. But for whatever reason, when the BRZ and its sibling, the GR86/FR-S, landed in North America, that spot was neutered. We ended up with a plastic placeholder that does absolutely nothing.
The aftermarket community didn't take long to fix that. Now, you can find a 4th brake light brz assembly in just about any style you can imagine. It's become such a staple mod that seeing a BRZ without one almost feels weird at this point. It's the kind of thing that makes you wonder why you waited so long once you finally get it wired up and see it glowing for the first time.
Choosing the Right Style for Your Build
Picking out the right light isn't as simple as just grabbing the first one you see on a parts site. There are a ton of different aesthetics to choose from, and you really want to match the vibe of your tail lights. If you've already swapped out your OEM tails for something like a Valenti or OLM setup, you definitely want the 4th brake light to match the lens tint and the internal LED structure.
Clear, Smoked, or Classic Red?
If you're going for that clean, "OEM+" look, a red lens is usually the way to go. It looks like it belongs there and blends in with the rest of the factory lighting. However, if you have a darker color car—like Magnetite Gray or Crystal Black Silica—a smoked lens looks incredible. It disappears into the diffuser when the car is off, but then pops with bright LEDs the second you hit the brakes.
Then there's the clear lens option. These are a bit more "tuner" style and look great on white or silver cars. The key is consistency. There's nothing that ruins the look of a build faster than having red tail lights and a smoked 4th brake light that doesn't quite match the shade.
That Sweet F1-Style Flash
One of the coolest features you get with a lot of these 4th brake light brz units is the F1-style strobe. If you've ever watched Formula 1, you've seen the cars' rear lights flash rapidly during rain or when they're slowing down. A lot of these aftermarket lights have a built-in module that makes the light blink three or four times quickly before staying solid when you hit the brake pedal.
It's a polarizing feature—some people think it's a bit much for a street car, while others love the extra attention it grabs. Personally, I think it's a great safety feature. We're driving cars that are significantly lower than the average SUV or truck on the road. Anything that gives the distracted driver behind you a "heads up" that you're slowing down is a win in my book. Most kits actually let you toggle this feature on or off with a simple wire tap or a switch, so you aren't stuck with it if you decide you'd rather have a standard solid light.
What the Install Is Actually Like
I know some people get nervous when they hear the word "wiring," but don't let it scare you off. Installing a 4th brake light brz is one of the more straightforward DIY projects you can tackle in your driveway. You don't need to be an electrical engineer to get this done.
Most of the popular kits these days are "plug and play," or at least very close to it. Usually, you're just reaching up behind the bumper, popping out a few clips, and swapping the physical housing. The wiring typically involves a Y-harness that plugs directly into your existing tail light harness. You might have to tap one or two wires for the "reverse" function or the strobe, but even that is usually done with simple T-taps that don't require you to cut or solder anything.
The hardest part is honestly just laying on your back and reaching into the cramped space behind the rear bumper. If you have big hands, it might be a little frustrating, but it's a 30-minute job at most. Once you see that light fire up for the first time, you'll forget all about the dirt that fell in your eyes while you were under the car.
A Note on Different Generations
It's worth mentioning that while the concept is the same, the actual fitment for a 4th brake light brz can change depending on whether you have the first generation (2013-2020) or the second generation (2022+). The bumper designs are different, and the wiring harnesses changed slightly.
The first-gen cars have a very distinct triangular shape that really leans into that "reverse fog" look. The second-gen cars (the ZD8 chassis) have a slightly different integrated look into the rear diffuser. When you're shopping, just make sure you're looking at the right year range. Most of the big brands have updated their designs for the newer cars, so you still have plenty of options regardless of which year you're driving.
Is It Actually Worth It?
At the end of the day, modding a car is all about making it yours. Some people want to go full widebody with a massive wing, and others just want a few subtle touches to make the car look "right." The 4th brake light brz mod falls firmly into that second category. It's relatively inexpensive—usually costing somewhere between $80 and $150—and it makes a huge difference in the presence the car has on the road.
When you're driving at night, having that extra point of light at the bottom gives the BRZ a much wider, more planted look from behind. It fills in that "dark spot" in the middle of the rear end. Plus, let's be real—watching your car reflect off a glass storefront when you're backing up or hitting the brakes is a great feeling.
If you're on the fence about it, I'd say go for it. It's one of those rare mods that is cheap, easy to install, looks great, and actually adds a bit of safety to the car. It's hard to find a downside to that. Just make sure you take your time with the wiring and secure everything with some zip ties so nothing rattles around back there, and you'll be good to go. The BRZ is a fantastic car out of the box, but it's these little personal touches that really turn it into your car.