Hello from the UK!
I don't have a Miata yet, but I do plan on buy on buying one, and boosting it. I will be fabricating as many parts as I can, so it will be a budget/reliable build. I've been on this site a few times, and will be using it a LOT when I buy the Miata...
Here's what I currently have:
She's a Peugeot 306 GTi-6 (I doubt you've seen this in the US?)
Full Jetex exhaust system
200cell race cat
Kevlar clutch with modified pressure plate
Ported head and inlet manifold
K&N 57i air filter
Spax adjustable suspension
Lowered about 40mm
Mintex green stuff pads
Stock power she runs 167bhp, but is around 185bhp now.
Please don't flame me as it's not a Miata....
Here's some photos: