Two supercars vroomed into the public eye on the same morning last week, punctuating a new period of optimism for the auto industry.a Both cars - the Acura NSX and Ford GT - are being made in the United States, which is a rarity for this strata of high-performance vehicles.a "I feel like, this year, there's no denying that happy days are here again," said Karl Brauer, a senior editor for Kelley Blue Book. "We're seeing a really optimistic automotive industry, and it's manifesting in powerful cars, exotic cars, fun cars, niche cars, convertibles."