Since I've never had one of those in my hands I can only go on what I've read and heard. From that, you might want to get to try the expensive grips on the gun for fit before you shuck out all that money for them. What I read was that the spacing of the grip screws is different on your Firestorm from a standard 1911. So grips made for a 1911 may not fit.
I've owned a couple of 1911's over the years that required non-standard parts. And if it was me, knowing what I know now about all the hassles I had with those guns, I would spend a little more money and buy a Springfield or other "standard", preferably American made, 1911 instead.
A forum community dedicated to Springfield Armory XD and XD-M series firearm owners and enthusiasts. Come join the discussion about optics, gunsmithing, styles, reviews, accessories, classifieds, and more!