Don't forget the 4.875 and 5.1 when you play with ratios, but you would need a 6th gear from a T56 to make them civil on the freeway... :)

A 6speed with my 4.875 would be nice on track (1st a trailer gear), but I have one track where the top speed will be limiting (a 4.3 diff would be nice there, Sportage gears require more work).

Playing with gearbox internals is a clear level above juggling with diffs. Cost/complexity of a custom 6th gear?

The 4.3 already makes 3rd "perfect" on the 6 speed. But I would prefer to not have a 5 speed with a retarded shift pattern.

I actually sent a friendly message to mfactory letting them know that all their s2k ring gear stuff should fit miatas and suggesting a 3.308 ratio be added. They already have one of the harder parts, getting the ring gear forging. They would just need to get a different thread pitch hobb and modify the program on their gear grinder. We'll see. I predict they will come back with their standard "get 25 pre-orders and we'll do whatever you want". OR they could just be selling mazda and kia factory r&p sets to the s2k people who dont know any better at a steep mark up.