My first serious modification was a 1.6 Miata.
I bought it stock from the factory

Then I placed an air filter
and then.....................................
Greddy turbo kit, E-manage, and many other stuff
I have designed the whole kit and installed it by myself and I have done all the dyno tests myself.. The car was 1.6 and had 110 hp and after the installation had 180 hp and 25 kg torgue at 4000 rpm. (0-60miles 6.9sec).
The turbo was running at 0.5 bar .
Very nice car and I have driven it many times in tracks....