This is an urban myth that was debunked previously, I remember a period where NC owners around the world were measuring the distance between wheel center and arch center and and the conclusion is that all markets are the same.
As mentioned before the NC2 roll center changed, this had no impact on the gap.
Wheel size, tyre profile and spring length are what changes the visuals and ride. Personally I think any variant of the NC with eibachs gives the best mixture.
You don’t state whether it’s your front wheel arch gap is much higher than normal, does it look too high?
You could have the twisted bush syndrome which is an easy enough fix.
Do a search for ‘twisted bush syndrome’ can’t help further as i am on my mobile at the more, if you can post pictures it will be obvious.
So, I’ve watched the Savage Geese documentary on the MX5, in which they spoke to US Mazda engineers, the engineering manager or so even said the car was a compromise between a part of the public that uses it as a cruiser and the other part the people who want a sports car and that the NC1 was essentially too soft in terms of suspension. If I were to keep the car (I have lost some faith in it after my 1.8 bearings have died) I am going to get me Bilstein B12 suspension. Meisters would be close to 1000 euro’s, B12 650. I have no real need for the adjustability, only quality of suspension matters. Theoretically I could use the 350 I save for an LSD 
Thanks for your suggestion. Gap is both at the front and rear.
So what exactly is the dimension from your wheel centre to the wheelarch lip? Really until you provide this information rather than it’s too much or looks wrong it’s impossible to provide anything meaningful. What gap are you expecting or looking for?
My car is at the garage, getting a new engine. When it’s back I’ll take some measurements.
It’s been a while ago, I got the car back but kept forgetting to measure the distance. I have done it now, results:
Center of wheel/hub to wheel arch lip:
Front - 15,6"
Rear - 14,8"
I’m somewhat surprised that the front seems to be a bit higher, I didn’t see it with the naked eye.
If you can afford it the Meister R CRD LT coilovers offer longer travel and 6kg/4kg spring rates. As far as your ride height measurements it appears to be way higher (50MM) at the front than it should be. The fact that the front/rear are so different would indicate someone has torqued the bushes in twist. The age of your car probably means the entire suspension is past it’s best anyway. You may end up chasing the issue and wasting money if you throw mis-matched parts at it.
So the front should be around 50mm lower? Right now it’s around 4,25" from tyre to wheel arch lip (rough measurement).
And i wouldn’t be surprised if the suspension has been replaced sometime as damping feels pretty tight. But I’m no expert on the matter.
Rear looks a bit low. Normally would expect 380 to 400 mm say 15 to 15.75in on standard springs. Lowered on -30mm mine was 355 or 14in both front and rear with 1/4 tank. Hope that clarifies where you are at the moment. Have you checked the rear springs as these seem liable to break around the top coils due to age and potholes.
Hmm, my 2008 NC, completely standard and well settled after 32,000 miles in 12 years sits at about 370mm (14.5") all around measuring wheel centres to arch lips a couple of minutes ago.
It has settled a few mm in the six years I’ve owned it, but only a few, less than five.
I think your front has twisted bushes, maybe from when the engine was out, they might have needed to take off the suspension (don’t know why, but it’s possible.)
Sorry, I mean’t generally accepted optimum ride height is usually around 345mm which places a arms in horizontal position. 345mm is lower than standard.
I have loosened the bolts on the upper A-arm and driven around like a rattling can around the block 
The front is slightly lower now but still 0.4" higher…also didn’t hear any sound of bushings untwisting. Anyone got other ideas?