I think they really do a good job on any connection that has a lip like the T and L connector of the cline. The only area they didn't seem to help mine much was on the connection to the fuel tank intake and fuel tank exhaust. Since those are straight tubing there is nothing for the clamp to grab on to. I solved that my leaving a fairly large amount of the tubing stick out of the tank. That way I was able to push the fuelline way up the tubing and it created a large surface to stick to. My tank is back near CG so I didn't have any issues with the long tubing sticking out through the firewall and kitting the engine.

I've been using mine like that with no issues. I guess I may not even have needed it, but since I had the clamps I thought it couldn't hurt.