Old school RA's were pretty stock like but stripped down. Then later they started getting bigger turbos, shorter gearing, DCCD, R180 rear ends, etc...then the GD chassis came along and the Spec C came about.
S20x models were a good bit different from the Spec C model which kept the stripped down model with forged pistons, shorter gearing, reduced weight (thinner glass), and some extra power.
We'll see what comes about.