2006 Mazda MX-5 Sport.
This is how it looked when I bought it. It has a 2.0L DOHC 4-cyl engine rated @ 170HP, a 6-speed manual transmission, the factory appearance package, and 17" wheels.
The first mod was a MazdaSpeed cold air intake. which required the removal of the front bumper for access. Luckily, it can be serviced from underneath by removing a plastic tray. I don't really notice an increase in horsepower, but the engine does seem to run smoother .

Next upgrade was MazdaSpeed Springs, Bilstein HD shocks, and FCM bumpstops. The springs lowered the car just over 1.5", a little more than I wanted. I have scraped a few speed bumps and driveways with this setup. But the improved handling is definately worth it.
And this is how it looks today. I added 5Zigen FN01R-C wheels with an ebay stripe kit. The wheels are 16x7 with an offset of 42mm. They fill out the fenders pretty well.
Update: I bought and installed the I.L. Motorsport 5 piece chassis bracing kit. Here are pics of the four braces that mount under the car.
Future mods will be more power, maybe ECU tuning or a header.