There are actually 2 different GNs in the pics, both with the same rims. The one with nitrous is my father's car. The first owner installed it and we haven't removed it yet. I think the turbo in the pictures was an LT-88, can't remember for sure. The nitrous has never been used except for just messing around to see if it worked when we first bought the car in '94.
3" downpipe into a 5-1/4" collector into dual 2.5" exhaust is/was the standard on these cars for many years. The car in the pictures now has a 4" downpipe. It's one of the rare, loud, rattles the dishes in the kitchen cabinets, solid cammed GNs around. No luck passing that one off as stock. Mine on the other hand could pass for stock if I didn't pop the hood.
Edit: on the subject of oil, my stock block car requires a 20w-50 to live while my father's faster car lives on 15w-40 in the summer, 10w-30 in the winter just fine.