Forza Horizon 6 Guide | Best Upgrades for Every Car Class

Choosing the right upgrades in Forza Horizon 6 can make a huge difference in how a car performs. Simply adding more horsepower isn't always the best way to improve a build. Tires, weight reduction, suspension, drivetrain upgrades, and aerodynamics can often provide more useful performance depending on the car and its class. 

In this guide, we'll cover the best upgrades for every car class in Forza Horizon 6, from D Class through R Class, and explain which upgrades you should prioritize when building a competitive car.

Best Upgrades for D and C Class Cars

D Class 

D-Class cars benefit most from upgrades that improve handling without adding unnecessary weight or using too much Performance Index (PI). Focus on keeping the car light and improving its ability to carry speed through corners.

Recommended upgrades: 

• Weight reduction  
• Wider tires  
• Better tire compound when PI allows  
• Suspension  
• Anti-roll bars  
• Brakes  
• Transmission  
• Small engine upgrades  

Weight reduction should usually come before major power upgrades. A lighter D-Class car can brake, accelerate, and corner more effectively without requiring a large increase in horsepower. Community tuning references similarly recommend prioritizing weight reduction over power in the lower classes. 

C Class 

C Class gives you more room to improve both grip and power. Start with tires and weight reduction, then use the remaining PI for suspension and engine upgrades.

Recommended upgrades: 

• Tire compound  
• Tire width  
• Weight reduction  
• Suspension  
• Anti-roll bars  
• Differential  
• Transmission  
• Moderate engine upgrades  

For road racing, prioritize grip and handling. For dirt events, build around the surface rather than using the same setup you would use for asphalt. 

Best Upgrades for B and A Class Cars 

B Class 

B-Class is a good balance between handling and power. At this level, you can begin making more significant engine upgrades, but tires and chassis improvements should still come first. 

Recommended upgrades: 

• Tires  
• Tire width  
• Weight reduction  
• Suspension  
• Anti-roll bars  
• Differential  
• Transmission  
• Engine upgrades  
• Aero when needed  

For road builds, spend PI on grip before chasing horsepower. A well-balanced B-class car can maintain speed through corners rather than relying on acceleration to make up time. 

A Class 

A Class is one of the most versatile categories in FH6. Cars have enough performance that suspension, tires, drivetrain, and aero upgrades become increasingly important. 

Recommended upgrades: 

• Performance tires  
• Wider tires  
• Weight reduction  
• Race suspension  
• Race anti-roll bars  
• Race differential  
• Adjustable transmission  
• Adjustable aero  

Engine upgrades  

AWD conversions can be useful for cars that struggle with traction, but they shouldn't automatically be installed on every vehicle. The added weight and PI cost can make a well-tuned RWD car the better choice. 

For A-Class road racing, the goal should be to build a car with strong cornering and braking, while retaining enough power for the straights. B and A-class builds are generally considered the sweet spot for balancing grip and power. 

Best Upgrades for S1 and S2 Class Cars 

S1 Class 

S1 Class cars are fast enough that poor handling can quickly become a bigger problem than a lack of horsepower. Tires, suspension, differential, and aero should be prioritized before maxing out the engine.

Recommended upgrades: 

• High-grip tires  
• Wider tires  
• Weight reduction  
• Race suspension  
• Race anti-roll bars  
• Race differential  
• Adjustable transmission  
• Adjustable aero  
• Engine upgrades  

The exact upgrade combination depends on the car. A lightweight sports car may benefit more from power, while a heavy car may gain more from weight reduction and handling upgrades. 

S2 Class 

S2 cars require even more attention to stability. At high speeds, a car that has plenty of horsepower but poor cornering and braking can lose significant time. 

Recommended upgrades: 

• Race tires  
• Wider tires  
• Weight reduction  
• Race suspension  
• Race anti-roll bars  
• Race differential  
• Race transmission  
• Adjustable aero  
• Engine upgrades  

Aero becomes especially useful for high-speed cornering. More downforce provides additional grip but can reduce straight-line speed, so the best setting depends on the circuit. 

For S2 builds, prioritize chassis stability and grip before adding more power.  

Best Upgrades for R Class Cars 

R Class 

R Class is designed for high-performance, track-focused cars, so upgrades should prioritize maximum circuit performance over general road use. 

Recommended upgrades: 

• Race tires  
• Maximum useful tire width  
• Weight reduction  
• Race suspension  
• Race anti-roll bars  
• Race differential  
• Race transmission  
• Adjustable aero  

Engine upgrades  

Aerodynamics are particularly important for R Class cars because maintaining stability through high-speed corners can be more valuable than gaining a few extra miles per hour on a straight. 

Don't automatically use maximum downforce, though. Technical circuits benefit from additional grip, while tracks with long straights may require a lower-downforce setup. 

R Class sits above S2 in the FH6 performance-class system and is intended for purpose-built race cars. 

Final Thought 

The best upgrades in Forza Horizon 6 depend on the car, class, and type of racing you're doing. Lower classes generally benefit from weight reduction and efficient handling upgrades, while S1, S2, and R Class builds need a stronger combination of tires, suspension, drivetrain, aero, and power. 

When building a car, don't simply install the most expensive parts available. Use your PI carefully, improve the car is weakest areas, and test the build after every major change. A balanced A800 or S1 build can be much more effective than a car overloaded with horsepower and poor handling.