You mean in addition to the NB1 vs NB2?

(my original 99 NB1 booster and ABS NB2 2003 booster are the same thickness. They're visually identical except for the angle of the vacuum fitting and the length of the pushrod)

--Ian

No, you can mix nb1 and nb2 as long as they have the same thickness booster, because if they have the same thickness booster they'll have the same thickness pushrod. Not all nb2s have the thick booster.

I haven't seen enough of the booster and master combinations in person but my understanding is that the thick/thin booster on NB2s is an ABS vs non ABS car difference and that the masters are interchangeable between all NB2 cars. The thread is super off topic now- andrew swapped his NA booster/master combo for a non ABS NB2 booster and master in order to improve brake feel.

NB2 Sport Booster/Master.

Sport brakes were standard 2003-2005.

Except they don't. As I said, my NB1 booster has a different length pushrod in it than my NB2 one, and yet the two boosters are the same thickness.

--Ian

I put a 1" 929 MC in my ABS 94 and did not need to change the booster. Based on this mt.net thread I was led to believe that I would, but the 929 MC bolted right up to the NA8 ABS booster. I'm guessing the NB2 15/16" MC would as well.

It's possible (likely?) that the appropriate booster has a higher boost ratio for lower pedal effort, but I actually prefer the higher effort, especially with Carbotech XP8/XP10.

FWIW, I have two NB2 boosters that are should work with the 15/16" and 1" masters, though I have not tested either of them. I'd be willing to let them go for shipping + $10.

Edit- moved to PM

If the issue is the pushrod length, just make sure you get the pushrod with the booster. Derp!

Are you 100% certain on the thickness? The booster ratio between NB1 and NB2 is different.

I didn't break out the digital calipers, so it's possible they differ by a few mm, but neither of them is the double-thickness booster that is discussed in the miata.net thread. I had them sitting side-by-side out of the car, and they are visually identical except for the length of the pushrod and the angle of the vacuum fitting.

I think the booster/MC combinations are significantly more complex than the ones that Keith looked up and posted in that thread.

--Ian