A CS (california special) is just an appearance package(different front/rear fascia hood/side scoops and decals). In 07 the coolant hose configuration changed most prefer the 07 + , also mid 08 the heads changed to accept one-piece spark plugs over the old style two-piece which there are problems with. Also if u want i reccomend a one-touch convertible top module mod i did it to my 07 and love it. Also in 09 the intake manifold changed to incorporate the CMCV (charge motion control valves) into the intake in a one piece design. Most prefer the pre 09 design where the cmcv assembly is seperate( also reccomend doing a cmcv delete plate mod, tune is required though). Hope this gives ya some answers thats all i can think of off the top of my head.