s1/2 doesnt really have an upgrade path to anything r2 specific. all the bronze parts in the pictures are new and the holes are all different. the upper and lower trans bulkheads are not compatible with r1/s12 chassis layout, mates to the chassis are moved apart and toward the extreme ends of the car.
motor mount is not compatible. uses a triangular hole pattern specific to the r2. r2 topplates likely not compatible.
to explain the shocks.. the oil filled usable body is the same length as the old r1 shock, i think they just took away some top and bottom thread and made the top caps a little shorter. the body are 1mm larger in diameter. pistons now have a 4 hole option. also undrilled pistons included.
shafts are still 26x3mm. not sure why they different part number.. maybe a revision to the coating?
they look the same.
the shocks travel the same but due to the shorter top cap, they took away the 3mm the shock towers took away on the s2. the springs are short, but my yokomo ones go right on without issue. you just wont need any preload for initial setting perhaps.
suspension mounts are unchanged from the r1.. this is a good thing. that setup works very well for adjusting the hingpins, though the r1 plastic bits fit kinda tight. hopefully these ones are a little easier to pop in and out.
they did include METAL pivots this time though which is nice. also the hd geardif included with mine has hex screws rather than the philips s2 users have had to deal with.
i really need to get mine together.. prob wont have time to do a video or anything as i had planned, but if anyone has any questions, wants pics ect i could do that. wouldnt mind getting my r2 out for practice within the next week.