BTW, the picture of the Sukhoi shows the blue stuff holding the cutoff pieces on the muffler. The muffler for that engine has restrictors in the ends of the pipes. I wanted to test to see if the restricted outlets made any difference. They didn't seem to affect the power of the engine but may or may not have affected the sound. I wound up using longer pieces of silicon and left them off. The inner diameter of the silicon matches the id of most muffler pipes, btw. It provides a very good replacement for the aluminum, btw. It gives in noseovers for example.