Yes he is right the GS and RS model come with a 420a NT motor where as the GST and GSX come with the 4G63T motor ad then the Spyder comes with a 4G64 motor the parts on the 420a are not compatable with the 4G63T to turbo it..it would take a new manifold, turbo, wastgate, fuel pump, injectors, fmu, missing link, lots of aluminum piping for intercooler and such, the the list goes on and on believe me I know, seeing as how almost all of them are sitting on the floor of my room