Hello.
I know this has maybe been answered before. However, in my pursuit of an answer, I never found a definitive yes or no. Each reply had its own idea.
So, asking it here:

Will 14” Rims fit on a base R56?
(14x8 ET+20, more specifically for my application)

Judge my taste as much as you want, we all own mini coopers.

I figure all wheels will fit differently, because wheels look different. I remember seeing a post about how certain 15”s could go on S’s, so why not justa’s.

I am specifically looking in to all the old JDM wheels, like star sharks and ssrs. Those tiny wheels look like they belong on a mini.

Anyways, if you guys are already collecting pitch forks and stuff, whatev’s. Thanks if you put them down.

 

Smallest I've ever seen is 15s, but why not try and find out? Are those wheels local?

 

Sure!
Most of the people in my area are focused on making their wheels larger, but maybe I’ll find a Miata club.

 

I have 15" wheels over 294mm R56S front brakes. Tight is an understatement. 14" over Just 280mm brakes? Very unlikely. You'll have to get some wheels and try. Alternatively, fit a small brake kit :-D
With 15x7 et40 rims, my r56 rear arms also needed a little fettling.
I was quite disappointed that my SE needs 16" wheels.to clear it's 280mm back brakes.