There's a drill mod for the stock BPV, might try that.
Clean your TB lately? IACV?
Getting it good and warm and sucking some distilled water through a vac-line carefully can help general carbon issues. I'll run a bit of methanol (gas-line dryer) alt with distilled water.
Enjoyed the Miata, but was a tad small for me. The Boxster was much better fit wise for me. Miata might have won for pure fun factor, but the Porsche won on comfort and capability over all. Of course the price tag was 2x...
06-07 WRX brakes are not brembo copies. They will save you weight on the corners, and they do look nice. I'm pretty sure you need an adapter or hub swap to get the rears to fit.