I ported and polished the head, the intake manifold and the throttle body. The manifold comes apart in two pieces, so it is much easier to get to all the innards. There is a great deal of smoothing to be done, as well as match porting to the head. I didn´t bore the TB, since I didn´t want to have to cut and match a new plate, but I did remove the ridge before the plate, enlarged the opening and the taper, and thinned the throttle plate shaft, as much as possible. I was chatting with Ryan about the TB and I couldn´t find all my numbers, but it seems that I increased the flow of the TB from 259 cfm to 282 cfm. On Miata.net, there is a figure of 300 cfm thrown around for the stock TB, but I think that is calculated for the 55mm size of the TB, not actual numbers from a flowbench, as I did here.
As far as power increases, I couldn´t pin anything down on these mods, alone, since I did a complete rebuild at the time. I mentioned to Ryan that I am making some power, however. I just ran a few times with my buddy in his Audi S4 and we were dead nuts even from 70-120, as well as, 15-90. Needless to say, we were both stunned, but I was the happier of the two of us.