so i was looking further into this and i have some comparisons. Ill be adding some information to the FAQ.
These are based based on a 9000 rpm shift with 4.78 final drive (personal setup). For the miata vs the FB gearboxes, the 1 - 2 shift is almost equal. But you do see improvement for the 2-3 and the 3-4 shifts.
Now the FC3S Type M transmission sees some improvement for all gears.
Which leads me to think that there could be benefits to running a 12a transmission if your on a budget, but certainly the full miata transmission is a good route to go. Im have considered using the the miata gears behind the PP but the Mazda box is of a weaker design than say, the T-5. NOW, other options that i am tempted to try involve the use of said T-5. A richmond gear T-5 can come in gears ratios that can keep the engine even higher in the rpms, but until i get an engine built and dynoed, i wont know what ratios i truly want. In the meantime the standard World Class 3.35 transmission is a close enough for me and has a good 5th gear pair for my final drive gearing for tooling around. The rally car might receive something far more drastic like a 5th gear 1:1.
Below is the miata vs. the Ford 3.35 WC T5
