I was thinking about buying the OMP MINI Cooper Upper Stress bar, but is it worth the money? I'm not going for looks, just performance.

 

unless you can find one used for cheap, i would say put the money elsewhere. i did not feel a lot of difference, if at all after installing mine. felt more with the cabrio braces actually.

otherwise, i would get the upper and lower set; THAT will be worth the money, and you save a bit as well.