I have an 87 mopar minivan that has been using a quart of oil each 400 miles since I bought it in 94. During the last 15 years I rebuilt the engine at 100,000 (not because of the oil consumption though) & since then it STILL uses a quart each 400 miles. It has about 220,000 miles on it now, running perfect. Oil is much cheaper than another car would be.
I rebuilt the engine in my daughter's 92 SL2, and it went from using a quart each 200 miles to using less a quart each 5000 miles. I dont really know how much, since I change the oil each 3000. All the engine needed were new piston rings and the ring grooves cleaned out.