If you're looking to wake up your machine, getting some gear from Aftermarket Assassins Pro XP kits is probably the fastest way to feel a real difference in the dirt. Most of us who picked up a Polaris RZR Pro XP did so because it's a beast right off the showroom floor, but let's be honest—factory settings are usually a compromise. Polaris has to account for everyone from the casual trail rider to the guy trying to jump sand dunes, all while meeting emissions and noise standards. That's where the guys at Aftermarket Assassins come in. They take a platform that's already good and make it act the way it was always meant to.
Why the Pro XP Needs a Little Extra Love
The Pro XP is a powerhouse, no doubt about it. But if you've spent any time behind the wheel, you've probably noticed a few quirks. Maybe the throttle feels a little lazy in the mid-range, or perhaps you've smelled that dreaded burning rubber after a long climb. Stock clutching and tuning are designed to be safe, not necessarily optimal.
When we talk about the Aftermarket Assassins Pro XP setup, we're usually talking about fixing those "safe" factory settings. One of the biggest complaints with the stock Pro XP is how the power is delivered. It can feel a bit linear or even restricted in certain gears. By opening things up, you aren't just adding speed; you're improving the overall driveability. It's about making the car more responsive to your right foot, so when you need to pop the front end over a wash-out, the power is actually there.
The Magic of Aftermarket Assassins Clutching
If I had to pick the single most important upgrade for this machine, it's the clutch kit. You can have all the horsepower in the world, but if your clutches aren't shifting correctly, you're just turning that power into heat and belt dust.
Their S2 clutch kit is pretty much the gold standard for the Pro XP. What's cool about it is that it uses magnetic weights. Instead of fumbling with tiny screws or complicated pins, you just snap these little magnets into the weights to adjust for your tire size and riding style. If you decide to jump from 30-inch tires to 32s or 35s next month, you don't need to buy a new kit. You just pull the magnets out, rearrange them according to the setup sheet, and you're back in business.
The real-world feel is where it hits home. You'll notice the engagement is much smoother, and it holds the RPMs right in the peak powerband when you're pinned. Plus, it runs a lot cooler, which means your belts are going to live a much longer, happier life.
Unlocking Horsepower with ECU Tunes
Once you've got the clutching sorted, the next logical step is an ECU tune. This is where the Aftermarket Assassins Pro XP performance really starts to shine. Their Stage 1 and Stage 2 tunes are incredibly popular because they don't require you to rebuild the entire engine, yet they provide a massive jump in "seat of the pants" feel.
The Stage 1 tune is usually a safe bet for those running 91 octane pump gas. It smooths out the throttle mapping, lowers the fan engagement temperature (which is huge for keeping the engine happy), and removes those annoying speed and rev limiters.
If you want to go a step further, the Stage 2 tune adds even more boost and timing. It's wild how much hidden potential is tucked away in that 925cc engine. When you pair a Stage 2 tune with a high-flow exhaust, the Pro XP transforms into a different animal. It's not just about the top-end speed; it's that low-end grunt that snaps your head back when you're coming out of a corner.
Let It Breathe: Exhaust and Intake
We can't talk about tuning without mentioning the exhaust. The stock muffler on the Pro XP is heavy, restrictive, and sounds a bit like a lawnmower on steroids. Swapping it out for an Aftermarket Assassins exhaust does a couple of things. First, it drops a significant amount of weight off the back of the car. Second, it lets the turbo breathe.
Turbos hate backpressure. By opening up the exhaust, you allow the turbo to spool up faster, which reduces lag. And let's be real—it sounds way better. It gives the RZR a deep, aggressive growl without being so loud that it gives you a headache after ten minutes of riding.
While you're at it, looking into their blow-off valve (BOV) kits is a smart move. The stock plastic diverter valves are notorious for leaking or failing under higher boost pressures. A high-quality aluminum BOV ensures that you're holding all the boost you're making, and it gives you that satisfying "pssh" sound when you lift off the throttle.
Small Parts That Make a Big Difference
Sometimes it's the little things that save your weekend. When you start pushing more boost through an Aftermarket Assassins Pro XP build, the stock plastic charge tubes can become a weak link. They've been known to crack or even blow off under pressure. Upgrading to silicone charge tubes is a relatively cheap insurance policy. They can handle the heat and the pressure much better than the factory plastic.
Another thing to think about is the drive belt itself. AA offers heavy-duty belts that are designed to handle the extra torque of a tuned machine. If you're going to be mashing the pedal in the dunes or crawling through technical rock sections, having a belt that won't delaminate at the first sign of heat is pretty vital.
Is It Worth the DIY Hassle?
One of the best things about these kits is that they're designed for people who actually work on their own stuff in the garage. You don't need a PhD in mechanical engineering to install a clutch kit or flash an ECU. The instructions are usually straightforward, and since these guys specialize in Polaris machines, everything actually fits the way it's supposed to.
The ECU flashing is done through a Power Vision device, which is basically a "plug and play" affair. You plug it into the diagnostic port under the dash, follow the prompts, and a few minutes later, your car has a whole new personality. It's one of those rare upgrades where the effort-to-reward ratio is heavily in your favor.
Real World Results
At the end of the day, all the dyno charts in the world don't matter as much as how the car feels on the trail. When you put together a full Aftermarket Assassins Pro XP package—clutching, tuning, and exhaust—the machine feels "connected."
The "clutch slap" and jerky take-offs disappear. The engine doesn't feel like it's struggling to reach its peak. Instead, it's snappy, responsive, and honestly, a lot more fun to drive. You'll find yourself holding gears longer and having more confidence when you need to power through a rough section.
It's also about peace of mind. Knowing that your cooling fans are kicking on earlier and that your belt is gripped tighter means you can focus on the trail ahead rather than staring at your temp gauges every thirty seconds.
Wrapping It Up
Updating your ride doesn't have to be a headache. If you're tired of the factory limitations and want to see what your machine is truly capable of, the Aftermarket Assassins Pro XP lineup is a solid place to start. Whether you just want a smoother ride with a clutch kit or you're looking to dominate the hill climbs with a Stage 3 setup, the components are built to handle the abuse.
It's an investment in your hobby, and considering how much we all spend on these machines anyway, making sure they run at their absolute best just makes sense. It's about taking a great platform and sharpening it into a precision tool for the dirt. Once you feel that extra kick of boost and the seamless shift of a well-weighted clutch, you'll probably wonder why you waited so long to make the switch.