Just so you know, if you ever show up at a Porsche meet with a Chevy or Mazda engine, you will be shunned or banned outright. Porsche owners HATE people who put non-Porsche engines in; in one of the Porsche Club of American bulletins (I steal them from my uncle) they talk about how they kicked out some guy who put a turbo Eclipse engine in his 914. Real purists, the Porsche bunch. Of course, they need to explain why they made a 150hp engine
On the other hand, there is probably a club of swapped Porsche owners somewhere...