Rules & Specifications

PRO3 Guiding Principle

PRO3 is a spec racing class for BMW E30s in the Pacific Northwest. It is the intent of the PRO3 class to create a restrictive formula for BMW cars designed to emphasize driver ability rather than design of the car. The spirit of the formula will not allow any modifications that would increase the cost of competition, nor lend to an unfair performance advantage.

Example Images of a PRO3 Build (Courtesy of Advanced Auto Fabrication)

Specifications (at a glance)

  • Body: 1984-1991 BMW E30 325i, 2-door or 4-door

  • Engine: Stock M20B25 6-cylinder (specific performance chip allowed)

  • Tire: Toyo RR or RA1

  • Differential: OEM ratios: 3.73, 3.91, 4.10, 4.27, 4.44 and 4.45

  • Wheels: 14" & 15” diameter allowed

  • Brakes: Rotors, calipers stock, aftermarket pads allowed

  • ABS: Not allowed

  • Suspension: Open, except remote reservoir shocks not allowed

  • Minimum weight with driver: 2,650 pounds

  • Minimum ride height: 5 inches to rocker panel

Full 2025 ICSCC Rule Book

PRO3 Specifics
Inside the ICSCC regulations is a PRO3 specific entry. Please refer to this before making any modifications to a race car built to run in PRO3 .