New to Supra's had a few Q's

[turbot11]

Hi my name is Chris, I was wanting to learn a few things about an 87 Supra, and thought this forum would be a good place to find out. I've discovered that the best way to learn about a car is to talk to the people that have them. My gf's kid is looking at an 87 Supra turbo he wants to buy, according to the owner it supposedly only needs a headgasket. I am an enthusiest of the turbo Dodge cars of the 80's-90's Daytona's, Shadow's, Omni's etc.. I know alot about those but I dont know jack about the Supra's lol
I had a few questions about the car and engine. It is an 87 turbo inline 6, only mods listed are a 3.5" from turbo to cat, and a 3" cat back along with some Tien ss coilovers. How would I find out what series engine it has in it? Are the engines cast iron with aluminum head, or all cast iron? If aluminum is it common and necessary for the head to be planed? Do these motors use torque to yield head bolts? What headgasket would you guys recommend, something like a multi-layered steel, or would composite be ok? I'm going to have him look for signs of detonation, on a turbo Dodge a blown headgasket could be an indicator of too much boost, lean condition. Is there anything particular to this generation of Supra he'll need to check for before considering buying the car? Thanks in advance for any help/info you guys could offer