Hi ,i whould like to know if there is an upgrade kit like stage 1.2.3 for sea doo rxp 155

Welcome! We haven't put a kit together for the 155 only because of the demand for 215 applications. Not enough hours in the day type of thing. However, there are several parts that will work on the 155 RXP that will improve performance.

Here's a list with links for more info:

Pump Wedge
Trims up your pump nozzle raising the bow of your craft for less drag and more control. Substantially improves top-speed and handling.

Throttle Conversion Kit
Quickly and easily transform your Sea•Doo thumb throttle into a more natural finger throttle with our Throttle Conversion Kit. No modifications to existing handlebars necessary and minimal downtime.

Thermostat Kit
Reduces the operating temperature of your modified 4-TEC® engine by 30°F for maximum reliability and performance.

Pro-Series Sponson Kit
Improves the handling of your craft with their superior blade & backing plate design.

Top-Loader Intake Grate
Unique wing design eliminates prop spin and cavitation while delivering improved handling and top-speed.

RIVA CREW
Please post and ride responsibly!!!

What about air intake, isn't there any better air intake for this than original? or not worth the investment.

Isn't it compatible with normal riva air intake used on turbocharged versions?

Unfortunately, there are no aftermarket air intake systems available for the non-supercharged RXP.