I built a 450rwhp turbo miata with 7k including the car.The car lasted me 13,000 miles. When i blew the head i decided to go ls2. It cost me roughly $1200 for everything besides the motor/tranny/rear end. That alone was going to be at least another 4k.

Now with that being said, upon completion of my project i would have had 400hp/400tq n/a. Sure it was going to cost me a hell of a lot more money to build, but in the end the potential was limitless. Getting the power to the ground was another obstacle all in it's own. My suspension/wheels/tires/bracing was about 4k itself.

I love the mazda miata. i am not the biggest fan of the first gen 1.6l (89-93) but from (94-2005) they are great cars. The newest gen is garbage in my opinion, i drove it and wasn't impressed.
the car was made to be simple, efficient, fun, and cheap. That it is.