I have a '95 Quad Four. Many similarities, but also many differences. Is that DOHC or SOHC? Makes a difference. The SOHC were the worst of the bunch. I'm up to a little past 129,000 miles, with really not too much trouble. A few things you would probably expect from lots of engines. A guy at work has a '92 with 180,000 miles. Another friend with a '94 has near 200,000.
Back in '89 or so, OLDS built one of these up big time, and it produced
1,000 hp. They set a speed record somewhere with it, not sure it's still a record. But impressive nonetheless. There used to be a place called Genertech Racing Development in San Jose, California that specifically designed parts and had a Sunfire in excess of 600 hp that they raced Acuras and such with. Mantapart, another company does this still. Only they are shifting toward the newer Ecotec. So it's been a pretty impressive engine to some, with lots of potential.
Tony