Originally Posted by pandabreads
Oh wow - good info! Shows how much i know at this point... I'm perfectly fine with 200-250 at this point with the car as well. I was just ballparking based on previous 4CYL turbo setups I've been around.
And by 4 cyl, you mean 4 rotor, correct?
In all seriousness, a Miata is not a heavy car. At a hair over 2,300 lbs, that '99 is easily 600-1000 lbs lighter than most other 4-bangers commonly considered to be "fast" (Lancer Evo, WRX, Integra / TSX, Focus, Golf, etc), and of course part of that lightness comes from being equipped with a transmission and differential that you can pick up with one hand.
200 HP / 200 ft.lbs was a magic number for years in the Miata world, though of course with modern engine management there are plenty of 225-250 HP Miatas being driven daily on the street. Beyond 250 HP, however, things start to get a bit dicey. There are certainly folks doing it, many of whom are on this forum, but it's not exactly a recipe for reliability.
Since you've already torn down the engine and bought all the expensive bits, you might as well go ahead and put it together. Off-boost performance is going to be a tad lackluster with such a low CR, but it does buy you headroom to play.
Forgetting about anything else for the moment, what are your plans concerning engine management (ECU, injectors, fuel system)? This seems to be the sort of thing that a lot of folks put off as an afterthought, but I far prefer to get it taken care of up front, before the turbo is even out of the box.