I would like to confirm what IvorMog/Bob reports.
The first gear on the MX5 gearbox is synchronised, and before hairpin bends I always have to shift back into first gear while driving because the final ratio of the 4/4 Sigma is much too long for B-road driving. The first gear of the Mazdabox has a very good gear length for a light car. I use all 5 gears of my 4/4 Sigma with great pleasure, so did I in the Plus4 Supersport. In the Roadster S2 and S3 I only used the 3 middle of the five gears with pleasure.
But as others have said, if a nice MT75 Box 4/4 Sigma crosses your path, that's a great car too.
There is one more point that I would note and that might even be in favour of the former 4/4 Sigma car.
I don't know until when exactly the Salisbury rear axle was fitted. Was it finished at the same time as the MX5 gearbox came along? The advantage of the Salisbury axle is that you can have a 4.1 final drive ratio fitted for manageable money. Then the first gear of the MT75 transmission becomes even more useless, but all those who have done it are absolutely thrilled here in the forum about the gain in dynamic feeling in comparison to the long ratio in relation to the other four gears, 2 to 5. On the contrary, the previously much too long 5th gear becomes included and usable.
Here is another in my view interesting point which has not been discussed here until now and it can also speak for the MT75 car if the timeline was the same:
I have the 2014 with the BTR rear axle. Already a few years ago, the experts from Williams and Techniques confirmed that this axle cannot be rebuilt with a shorter differential for any amount of money which means it is impossible.
If you want to have it sportier with the BTR rear axle, then you need a completely new one to go from 3.7 to 4.1. That is far too expensive and out of proportion. That's why I tuned the torque on my 4/4. But it is important to know that you cannot do with the BTR axle the same in an easy manner than with the Salisbury axle.
A little side effect: The 4/4 with the Salisbury axle looks a little bit more classic and so beautifully proportioned. My 4/4, on the other hand, doesn't look quite as proportioned because the BTR axle is wider. This gives these cars a more trapezoidal appearance - wider at the back and narrower at the front in relation. It's not the end of the world. But those who enjoy subtle aesthetics will appreciate the difference and would chose perhaps the earlier 4/4 Sigma for this reason.
