G'day mate, well have to agree to disagree on that one, they act as excellent mud guards, hava a look at the underside of a Drifter that has spats and one that doesn't. I also have a mirror fitted to my left hand spat, or as I call it, my ''Fuel guage'' LOL - They will not add 1/10th of a knot of airspeed though hahaha
To answer the original post, I beleive there is a guy called Andy (?) in the northen NSW who has moulds and can make, if you contact Kiwi at Boonah 0438 250 404 I'm pretty sure he knows how to get in touch with him, Hope this helps.