Sea-Doo RXP-X 300 Stage Kit Performance
GT40 Performance Stages
Three rider-tested performance packages. Manufactured in the United States. Performance-tested on the platform.
Pick your stage
Each stage builds on the last. Same platform. Different ceiling.
Foundation Build
Open-loop cooling + ribbon delete + ECU tune. The starting point for every serious build.
~25–30% over stockBreathing Build
Stage 1 + free-flow exhaust + high-flow fuel delivery. Unlocks the mid-range.
~45–50% over stockRace-Prepped Build
Stage 2 + drive-train: pulley, clutch, impeller, ride plate. The ceiling for this platform.
~65–75% over stockCompare GT40 Stage Systems
What's included, what it gains, what it takes to install. Same platform — different ceiling.
| Feature | GT40 Stage 1 System | GT40 Stage 2 System | GT40 Stage 3 System |
|---|---|---|---|
| HP Gain | +25–30% | +45–50% | +65–75% |
| Fuel | 91 octane | 91 / 93 | 91 / 93 (E85 optional) |
| Reliability | Excellent | Strong | Race-focused |
| Skill Level | Beginner DIY | Intermediate | Advanced / dealer |
| Cooling Upgrades | OLC included | OLC included | OLC + intercooler bypass |
| ECU Tune | Yes — included | Custom dyno tune | Custom dyno tune |
| Install Time | ~3 hours | ~6 hours | ~10+ hours |
| Price | $899.99 | $2,499.99 | $4,999.99 |
Why GT40
What you'd build for yourself if you knew the platform.
Built and tested in the USA
Bonney Lake, WA. Bench-built, water-tested, re-verified before it ships.
Real rider-tested setups
Every spec on this page was validated on actual skis under real-world load. No bench math.
Performance-focused support
When you call, you're talking to people who ride the 1630 ACE and build the kits — not a call-center.
Carefully matched packages
No random Amazon-grade brackets. Every part in the bundle is sourced to work with the others.