Which cars came with a stock dual exhaust system?
Starting in 1989, cars with the G92 option got the dual cat system, but the post-cat exhaust is tied into a single 3″ pipe and fed through a single muffler with dual outlets. GM rated the dual cat version at 10 more HP than the single cat versions. Putting a good aftermarket system w/ mandrel bent pipes and a free flowing muffler will still give you better power though on a car with dual cats.
