Turbo and Heating Questions from a Beginner

[wood]

hi men

couple of questions that i am hoping you old hands will be able to help me with concerning a 1990 uk supra

re the turbo : how can i tell if it is stock factory or aftermarket as there is some discrepancy on the paperwork ... any links to images ?

re heating : i have heard a lot about a design flaw on the early supras that led to engine overheating and blown head gaskets ... what are the tell-tale signs of this ? engine sounds great but interior heating will not heat maybe ???

any help appreciated over here ... thanks !