For the 05 R50, sport suspension was standard.
There is also sport suspension plus (same struts and sway bars as the Cooper S, and similar springs to the S).
If you can see a label on the struts, run the part number on realoem.com and you can see if it's for the
SS or the optional SS+. Also, the sway bars will be 22.5mm front, 16 mm rear for SS and 24, 17 for SS+.
Also, the struts and the rear bar may have been replaced with oem or aftermarket parts since 2005.
People rarely replace the front bar, however.
There's also a JCW
suspension with its own springs, struts, and bars (although I think the front bar is unchanged
on the JCW