SP groups similar cars on a "line" in the rulebook. If a car is in the same grouping or on the same "line" then you can use update/backdate. To be on the same line the cars have to be virtually the same. So Miata in CSP is listed as 1990-2005 on one line and MX-5 2006-2013. The 1990-2005 share a lot of the same parts and in many ways are essentially the same car - the 2006-2013 is clearly a different car. It shares nothing but the name and the concept with the earlier cars
The original logic behind it was that in SP there shouldn't be an advantage to a certain model or year of what is essentially the same car. It was intended for simple things like if you have a leather car you should be able to put cloth seats in, or a 6 spd can be swapped for a 5 spd, or a open or viscous diff can be replaced with a Torsen. Basically allowing you to simply convert a car to a specification that could have been ordered. The logic and rules of SP have spiraled out of control which leads many people (me included) to believe that SP is going to either get eliminated, severally restructured, or merged into SM in the next few years.
Well that settles it. Since one of the major part that's missing from car appears to be a loop hole, I will continue to make sure my car is an all round track, time attack and local, not National, Autocross fun car. Guess if I ever do a National I'll just go expecting to lose.
Last edited by See23 on Thu Jun 23, 2016 8:10 pm, edited 1 time in total.