I like the definition from the ACCA: STOCK CLASS: Vehicles exhibited must be configured exactly as shipped from factory (NOT DEALER). Cars with Dealer add-ons such, as wheels, other than stock tires, side moldings, etc. can enter this class with deductions for same. Radios, paint color, tires, etc. must be as shipped. A/C must be factory installed except 240Z which may have same A/C as installed by dealer, i.e. ARA or Frigid King, with basic York compressor. Daily Drivers can enter this class if desired. The reason is that of documentation. You can look up what was on the car from the build sheet (which has the add-ons) or the manufacturer's brochure. That way you won't have to depend on memory. The new preoblem we have now is that since these 240Zs are being reduilt/refurbished/whatever, we (or they) need to decide if the condition at sale is F-stock, rebuilt-stock, or whatever. I haven't heard of any non-stock extras being added to the cars buring rebuild, but the the possibility is there. thx