SRX: What to Upgrade First ranks the 305 Sprint parts by performance per dollar and gives you the buy order.
The 305 Sprint car has four upgrade categories: Engine, Chassis, Suspension and Tires. Each category offers six components at each of three ranks, for a total of 18 per category and 72 listed components overall. Rank 1 is initially available; Rank 2 requires Facility Level 2; Rank 3 requires Facility Level 3.
Every category follows a consistent pattern: Standard, Performance, Performance Plus, a durability-oriented alternative, its Plus version and a High Precision combination. The initial standard part displays performance 2/10 and durability 10%. The best Rank 1 combination displays 10/10 and 80%; the best Rank 2 combination reaches 20/20 and 90%; the best Rank 3 combination reaches 30/30 and 100%.
Performance versus durability
The menus make the trade-off visible. At Rank 1, a Performance Plus component generally shows 9 performance and 20% durability, while the durability-oriented Plus alternative shows 8 performance and 70% durability. At Rank 2, the corresponding values are 19/30% versus 18/80%; at Rank 3 they are 29/40% versus 28/90%. The latter gives up one displayed performance point for 50 additional durability percentage points.
This is a specification comparison, not proof that one choice is faster or cheaper over an entire season. In particular, performance points across different categories should not be assumed to have identical effects on lap times.
What to upgrade first?
The most practical decision is often whether to buy an affordable Rank 1 part now or save for a facility unlock and a Rank 2 part. For example, the High Precision Rank 1 tyre set costs $6,745, with 10/10 performance and 80% durability. The Rank 2 High Precision tyre set costs $15,505 and requires Facility Level 2. The Rank 3 High Precision set costs $34,245 and requires Facility Level 3.
Buying an intermediate part delivers an earlier improvement, but may mean paying again when the next rank becomes available. Saving for a higher rank avoids that intermediate purchase, but delays the on-track benefit. Because the facility itself does not improve the car, budget for both the unlock and at least one usable part before treating a facility upgrade as an immediate performance gain.