Spark plug wires.
9 years with my Miata.... I store it every winter and bring it out in the summer. Every year it puts a big grin on my face.
NOTHING has gone wrong since I owned this car... coming up on 160,000 km, I probably need to fix a front end oil seal and I'm on my 3rd set of spark plug wires (they last about 50,000 km.)
On long runs the Miata can be a bit noisy with the top up, buy it with the AC. I simply can't recommend this car enough. As long as you're prepared to live with its impractical configuation, it's a simply superb product. A great car and an even greater 2nd car.
As for performance... some may crave for more power (OK even I do sometimes) but there are TONS of excellent aftermarket kits available (the Miata drive train is EXTREMELY robust) and even stock, my 10 year old MX5 will get to 190 kph with very little drama (just did this in a fit of silliness the other day).
If you like the car you can buy it with 100% security.
I recently purchased a 1990 MX-5 of my own and it's a great little car.
I wish I still had mine. 2 weeks ago I got hit head on by a Grand Am. I cannot believe how well this car held up and protected me. This was something I was always worried about with this car. I just had some superficial scrapes and was sore, but came out OK. And now I am looking for a replacement.
My mx5 had 113,000k when I bought it in 2000. It now has 250,000k and it still makes me smile...Dave.