Usually m90 springs will give ~295 fps and an m100 will give ~325 fps, so it depends on how much leeway your site gives over that limit. For example some sites list 328 as their limit but have a tolerance up to 350, any gun even .1 fps over can't be used.
Because of this I always choose m90 springs for my rifles as it's comfortably within most site limits even if I sacrifice that extra fps boost.