I bought the Miata for $2500 in early 2020. The engine had multiple oil leaks and was overheating, the clutch master cylinder was leaking, the suspension was shot, the upper ball joints were torn, the wheel bearings were in poor condition, the soft-top was ripped and excessively leaked, there was missing hardware for the end links, the seats and steering wheel were torn, the wheels and tires were in poor condition, and all the fluids were old. I made it my mission to restore the car back to full health and turn it into a backcountry/track car while learning new things every step of the way. Everything I fixed/installed on this car was the first time I had ever done it.
Like any 19 year old who buys his first fun car, the first thing I did was replace the stock exhaust with a large obnoxiously loud one :). At the time I didn't have any tools, so the entire exhaust system as well as new gaskets were installed using a 4" crescent moon wrench on the bolt and my friends calloused hand holding the nut on the other side.
After replacing necessary components to achieve a functional car such as engine seals, a new radiator, wheel bearings, a new soft-top, and fluid flushes it was time to upgrade some of the old parts. I replaced a faulty combination switch, installed an aftermarket momo steering wheel with an NRG quick release, 15X8 Advanti Racing Storm S1 wheels with extreme contact sport tires, V-Maxx XXtreme coilovers, new stock upper control arms, FM sway bars, and finally a hard dog roll bar because safety comes third.
After some time of enjoying the naturally aspirated car, it was time for a power upgrade. I installed a FM turbo kit, MSPNP2 aftermarket ECU, DeatschWerks 550 CC/min fuel injectors and 165 LPH (Liter per hour) fuel pump, Turbosmart boost controller and solenoid, AEM AFR gauge, Innovate water temp gauge, and an upgraded clutch and lightweight flywheel.
Building this car was one of the most humbling and enjoyable experiences I have ever had. The foundation of my knowledge in mechanical engineering is rooted in the work I've put into this car. I learned to deal with failure, fix my mistakes, and learn new mechanical skills and concepts along the way. Most importantly I have made life long friends and unforgettable experiences.