I love my 1990 NA. It's a cammed 1.6L with about 140whp. Engine was rebuilt and tuned by a guy who builds spec miata race cars and has been doing so for more than 20 years. Rev's out to 7800rpm, still on the stock ecu by manually adjusting the AFM, fuel pressure and timing (Old school method). All the power is over 5krpm. Very fun to drive up in the rev range and it sounds crazy driving around the roads with a racing manifold, decat and a borla backbox! Love its raspy sound and its pops. All rust has been cut out and the car has been resprayed.