lets set are the fuel system
fuel pump
remove the return line

wiring
you need the whole lot from the st

suspension
front st shocks and springs
rear on the st is just lower

exhaust
you need the whole system

engine bay
you need everything out of the sts bay bar steering rack. coolant system pas pipes engine mounts really everything.

odd stuff
headlights if yours is a mk1
speedo ect

really ive gone from 1.6 to 2.0 and the only diffrence was i didnt have to change any of the fuel system.