Race Sim Studio’s GT-M cars have been the go-to for modern GT3 content in Assetto Corsa for a while now. But their new GT-MX class is where things get shaken up. Instead of trying to stay inside GT3 regulations, GT-MX is RSS basically saying: what if we take familiar GT cars, remove the rulebook, and build the versions that exist purely to be fast?
That is exactly what the GT-MX Protech P92 F6 Renn is. It’s RSS’s take on the Porsche 911 GT3 R Rennsport, a limited-run, track-only monster that turns an already capable GT3 platform into something far more extreme. RSS describes GT-MX as an “unrestricted performance class” outside standard GT regulations, with increased power and refined aero, sitting somewhere between contemporary GT cars and higher-end machinery. And on track, it absolutely feels like that brief was the entire point.
Find the Protech P92 Renn on the Race Sim Studio store:
Despite the name, the 911 GT3 R Rennsport is not some vague concept car. Porsche built it as a limited-edition track tool, based on the 992-generation GT3 R, designed specifically to go beyond what GT3 homologation and series regulations normally allow.
The headline number is the power. Porsche quotes 456 kW (620 hp) at 9,400 rpm from a naturally aspirated 4.2L flat-six, plus a target weight of 1,240 kg. That’s already a big jump over a normal 992 GT3 R, which is typically quoted around the mid-500 hp range depending on BoP.
In other words, this is the no excuses version. Same vibe as the other cars GT-MX is aiming at, like the 720S GT3X-type builds and other unrestricted specials, just done the Porsche way.
Like the McLaren GT-M release, install is straightforward:
No weird extra steps, no manual sound installs. The only thing worth mentioning is the v1.1 update, which RSS says included launch control refinements, minor texture updates, and extra object vibration/motion so the car feels more alive.
If you’ve driven any of RSS’s newer releases, you already know what I’m about to say. The exterior is borderline flawless.
Headlights, aero surfaces, carbon work, panel transitions, and the little details that most mods skip are all modeled at a level that makes the car look official. It’s easily a 10/10 visual package. Textures and reflections are excellent, and the overall presentation is clean and modern.
The interior is just as strong, and it’s full of those small details that make VR and cockpit driving feel legit. The compressor tank and what looks like the battery placement in the passenger foot area is exactly the kind of race car realism detail RSS always nails.
The only real problem I ran into is with the interior rear-view camera: the airbox does not display correctly and you can get repeated textures from previously displayed frames. This might be mod-side, or it might be something weird in a specific setup. Either way, it’s worth flagging because it breaks immersion when you notice it.
This thing sounds insane.
It matches what you’d expect from a 992 GT3-based race car turned up to 11. The revs feel more aggressive and more track weapon than a normal GT3 R vibe, and the sound is one of the biggest reasons this car feels special even before you start pushing lap time.
No looping, no clipping, no obvious low-quality samples. It just sounds like a car that wants to live at high RPM.
This is where the Rennsport character really shows up. It feels fast immediately, and not in a fake way.
I tested at Spa and Detroit Belle Isle, and the car’s personality is very consistent across both. It is not a snappy rear-engine deathtrap. It is more like a heavy-hitter that makes you manage front-end behavior.
The Detroit T1/T2 complex is the best example. That exit is hard to get right because if you over-slow it and wait too long, you push wide. If you try to rotate it too aggressively, you can slide the entry and lose the line. There’s a narrow window between rotating it and simply washing out. Once you find it, the car is fast. But you do have to drive it properly.
Braking stability is good overall. The rear will rotate on entry when you ask it to, and that’s a big part of making the car work. The tricky part is finding the exact margin between good rotation and sliding out.
Kerbs are fine. A little bouncy at times, but pretty normal for Assetto Corsa, and nothing that felt broken or unpredictable.
The standout moment for me was honestly the first lap leaving the pits at Spa. In a normal GT3, I’m not always taking Eau Rouge flat on cold tires without thinking about it. In this, it felt confident enough to do it with ease, and the acceleration surprised me. It feels like it lives in that RSS-described space between GT3 and something more exotic.
RSS packed the usual high-end stuff in here:
The coolest extra is the visible functional air jack system. In a pit scenario, the car will display up on the air jacks. It’s a small detail, but it adds to the feeling that this car was built with the full experience in mind. It’s also a new feature for AC, which we always love to see.
Liveries are strong too: 12 total, with copyright-friendly branding. A mix of classic graphic styles, plain colorways, and a couple camo options.
The first downside is the one I already mentioned: the rear camera display glitch.
The bigger downside is more about how this fits into RSS’s catalog. From a user perspective, it’s hard not to think: this is based on the Protech P92 GT3 car, so why isn’t it an add-on variant to that platform? If you already bought the P92, buying the GT-MX version too can feel like double-paying for closely related content.
There’s also the “where will this be used” question. In real life, the Rennsport exists outside normal GT3 rules. In Assetto Corsa, that means it’s probably going to see less action in league racing compared to standard GT3 cars. You really have to want the specific Rennsport experience to justify it as a second Porsche in your library.
That said, at £4.19 standalone, the value is still strong. The quality is there. The pack pricing is also fair if you actually want the whole GT-MX idea, because RSS is one of the first major teams to really lean into this unrestricted niche in a serious way.
This is a classic RSS release in the best ways: elite model quality, strong sound, and physics that feel grounded and believable. The understeer-heavy mid-corner balance will not be everyone’s favorite trait, but it does feel like part of the rear-engine fast but demanding Porsche identity, just scaled up into an unrestricted track weapon.
If you buy it standalone, it’s hard to regret. If you already own the standard P92 GT3, it becomes a more difficult decision. What car mod should I review next? Drop your suggestions in the comments.
