I've seen radiator muff's on wotsername's stand, the two racing sister's in Bradford wotsitcalled aaaagh!
Anyway, they are proper so to speak, bespoke items with a removable flap for the main rad part and an open square for the intercooler bit, not sure if you can cover the intercooler bit, would think these are more suitable for winter driving rather than mud/water splashing tho.
Wish I could think of their name... right on the tip of my tongue as well!! :oops:
Chris W