Sort of. Technically speaking you're getting to where there were differences between there being dimples cast into the edges of the cross lace near the centercaps versus not, and the construction of the pieces... it's splitting hairs. Aside from seeing the dimples or lack there of, basically, yes, same rim for your purposes. If you had a real gnx the answer would differ.
Depends. Is your v6 a 3.8 2bbl carb, or, a 4.1 4bbl carb? The 4.1 used the same rolled fillet crank as the 84-87 sfi v6. To oversimplify starting where you are (1983) there were 3 versions of blocks (four counting that 4.1). You had the 83/84 3.8 with a 14 bolt oil pan. Next, you had a 1985-only 20 bolt oil pan, but, the lifter valley looked rough and unrefined (comparatively). Then, 1986/87 you had the 20 bolt pan but a beefier lifter valley. Now, that 86/87 block, called a 109 block based on casting number, is thought of as most desirable and has a raised area that can be drilled/tapped for the 86/7 oil return line even on the basic 2bbl carb models. However, even earlier models can be drilled with a fitting added so it's not a huge deal.
Typically in the 84-up years you see the "8445" head castings, but, again, I never saw much wrong with the old 0293s personally.
I'd take advice with a grain of salt as far as "throw the turbo on" unless it comes from someone who knows the cars and looked at the casting numbers of what you have. And even then, it's not their mess to fix when it pops.
