Yeah, the Mazdaspeed MX-5 is sooo tempting. Here's the upgrade path as recommended by Flyin Miata. (
http://flyinmiata.com/tech/MSM_upgrades.php)
Recommended Mazdaspeed upgrade path
We sell a lot of parts for the Mazdaspeed. It's enough to really confuse you, isn't it? Well, here's our recommendation on a good upgrade path to take.
1. Intake. Ideally the complete intake kit, but the intake only is a good start. This will give you a good boost in power for a low price.
2. Downpipe. It's probably the most popular upgrade for Mazdaspeeds and for good reason. It will smooth out the boost rise and make the car more driveable under all conditions. Why wasn't it number one? Well, it was a close call. It's a little more difficult to install than the intake, so it got number two.
3. Exhaust. Get rid of the last restriction in the system for more power and a nice purr from the tailpipe.
4. Intercooler. It's not going to necessarily make any more power, but it will prevent your car from getting slower as it heats up. Even stock Mazdaspeeds suffer from heat soak and the higher power from other upgrades only makes this worse.
Okay, there's the easy stuff done. The car is now at around 200 hp at the rear wheels, makes a great noise and doesn't get slower as you drive it. The stock injectors are at their limit, so now it gets a little more expensive.
5. Hydra Nemesis. Not a cheap upgrade, but one that makes a big difference to the driveability of the car. You won't believe how many little bumps and odd behaviours exist in the stock ECU programming until you feel the smoothness of one with a Hydra. Spoolup will improve as the Hydra will run more timing in the lower ranges. But to make any more power, you need...
5a. 550 cc injectors. With great power comes the need for great amounts of fuel. These will solve that problem. Not compatible with a stock ECU.
By this point, the car is able to run 240+ rwhp safely on the stock clutch. We offer all of these parts together as part of our Big Enchilada package.