Why not make them yourself? All you need is a section of the pipe you have, cut triangular shaes out the end. Easiest is to cut a short section of pipe, cut it lengthwise in 4 equal aprts, trim these 4 to a pointy/triangular shape and then trim the bottom part so that you can make a piramid out of the 4 sections that fits flat on the pipes. It's kinda hard to explain but you'll have to fishmouth the ends a bit.
Yeah im gonna give it the old college try (10 minutes of trying, followed by a six pack...followed by banging on it til it works ) but Yeah I'm going to look into it, either that or ill use a flat piece, its for a set of turbo headers, so it might not actually make a huge difference, but, ill give it a try.