Costs vary by chassis condition and how much of the performance package you need to add, but the program was built around keeping used-car prices and modification costs low and predictable. In general, Mustangs and MX5s can be bought and built for $25k and under, while the Cayman, offering more performance and luxury, starts around $50k for car and kit. Owners can certainly spend more for a newer, nicer, lower mileage example, but Club Spec offers a bit of a departure from classes where the fastest, often most expensive builds keep pushing costs up for everyone.