I've got a throttle body for sale. It came off a Lexus 400 something. Had a V8 under the hood. Throttle body measures 3" I.D. It's huge. Includes the TPS sensor and everything else that was on it. Also has a neat progressive throttle linkage so it opens slow at first, then gradually opens faster the more you open it. Like last 1/4 of travel open is the last 1/2 of the way. Would love to do that to the miata somehow. Anyways, 60 shipped and it's yours. Could use this for a custom intake manifold build or a 3" cutout for your exhaust. Or as a paperweight.

Pictures in a bit, waiting on camera batteries to charge.

 

That thing with the progressive throttle linkage, I remember some guys selling a replacement thingy that the throttle cable attaches to on the throttle body. Does exactly what you describe.

 

Pictures..

But sounds like a vq45 tb. 90mm. Closer to 3.5" I think?

 

It measure 3" ID on the inlet, but 2 3/4" ID on the other end.