As we continue to prepare for 2024, there have been a couple of updates for both Club Spec Mustang (CSM) and Club Spec MX-5 (CSX). All changes have been incorporated into the rulesets online here, as well as outlined below (changes indicated in red). 

Club Spec Mustang (CSM)

Eligible Vehicles

2005-2009 Ford Mustang GT Coupe, Convertible (S197 Chassis)

Required Performance Kit

C. Tires: Goodyear F1 Supercar 3 (220 Treadwear), size 275/40R18

Club Spec MX-5 (CSX)

Vehicle Requirements

6-Speed Manual Transmission or Automatic Transmission
Minimum Vehicle Weight, as weighed without Driver (lbs): 2500

Authorized Changes/Modifications

Safety

B. Interior Modifications and/or soft top removal, as required per manufacturer's installation instructions, are allowed to facilitate the installation of safety equipment. Interior modifications should be kept to the minimum required for installation; factory restraints must be retained.

Engine and Drivetrain

F. An oil cooler is allowed provided no unauthorized modifications are made to perform the installation, Mazda Motorsports Oil Cooler Adaptor with Lines Part# 0000-01-5511-KT is recommended. Engine oil coolers and lines may be added or substituted (including oil to coolant heat exchangers) provided they serve no other purpose. It is highly recommended to use the Mazda Motorsports oil cooler adapter and lines (0000-01-551-KT), as a traditional sandwich plate adapter installed to the factory oil filter housing is known to cause the housing to fail.
G. Engine cooling radiators may be replaced with alternate parts subject to the following restrictions:
a. Radiator core dimensions (width, height, thickness) cannot be smaller than the standard part
b. Radiator must use OE radiator mounts
H. The radiator overflow tank may be substituted provided the replacement tank has the same capacity, function, and mounting location as the original tank