currently i have an 06 R50 with regular suspension (No-sport)...and the wheel gap is more then i would like. (Ideally would only want to drop 1/2')
i have a set of Koni FSD coming in the mail, and these are meant to be paired with OEM springs only.

if the R53 springs (i believe they are call sport suspension plus ((which an option package for R50)) sit lower, then i can pick up a set (plenty at my local junk yard) to pair with the new Koni's.

don't care about the spring stiffness, just care about the ride height.

ultimately, trying to reduce the wheel gap.

read/search a lot of posts, no one really mentioned the ride height between the two.

 

The R50 and R53 have the same ride height, but it's slightly more complicated than that.
There are several versions of R50 regular and R50 sport springs, and several versions of R53 springs.
Some of the R50 sport choices coincide with some of the R53 choices.
The ones that go with a particular MINI depend on the options (actually the combined weight of the options),
and are chosen so that the ride height is about the same on a bare bones car as well as one with sunroof, compact spare, auto transmission, and other options that add weight.
This means that if you use R53 springs on a R50, it will actually sit a little higher, especially in the front.
The BMW ETK has a "spring table" function where you can plug the model and options and determine which spring is correct for that MINI.