Some observations from the swap:
Doing the NA -> NB conversion will “nickel and dime” you like crazy if you don’t already have a stable of miata parts. Even with a complete donor, I had to source an NA8 alternator, NA8 cat, OEM exhaust manifold, fuel rail, and tons of other little bits. Granted, I did complicate things by using a Protege valve cover, but still, it wasn’t cheap.
Doing a complete drivetrain swap is actually a great opportunity for cleaning and refreshing everything from seals to belts to hoses. This does drive up the cost, but also improves the finished product and is worth the time/money (IMO).
The car is a total blast to drive. Even with a stock motor, stock NA exhaust, and a flawed DIY intake (still need to build something proper), it has plenty of power. The NB engine seems smoother than the 1.6 and lets you drive the car in 5th gear at any speed with enough torque to accelerate in traffic without downshifting. With 205-series S-drives, the car doesn’t have tons of grip, but is still very nimble. I plan on getting rid of A/C and depowering the P/S in the future.
Keeping everything OEM means that I can get parts for it at the local auto parts store. No fancy aftermarket parts to break. I’ve put about 3k miles on the swap and its been dead reliable.
Rattles and squeaks. The earliest NA6s are 21 years old, and even one in pristine condition (no rust in the Northeast, garaged year-round) the interior rattles and buzzes like crazy with the hardtop up. My next step to track some of the sources down and stiffen up the chassis, but still, its an old car.
