My son has a 1989 Miata with 200,000+ miles on it and it still runs great. It's no more dangerous than any other car so long as you don't plan on flipping it over -- very rare --
There are thousands of aftermarket parts and add-ons available plus dozens of clubs (which are great fun and informative). Try to purchase one with a good top -- they only last about seven years before they begin to fray around the edges and leak. A replacement unit costs about $600. Rear brakes will require caliper replacement when the pads are worn out ($68.00 per caliper from Autozone) and if the clutch needs replacing go ahead and buy a high performance unit. It only costs about $50 more and will double the lifespan. If you buy a Miata with no maintenance records go ahead and have the timing belt replaced. Miata engines and drive systems are as tough as they come, get a solid 34 mpg and require only minimum upkeep. If you don't have to haul lots of luggage, (the trunk gets crowded with a shoebox in it), and passengers then you will love this car.