..are you fitting the insulating base-plate etc by any chance?
Does anyone know of the real world gains of fitting superflared trumpets over cutting the originals down - my originals do flare a little at the top but I have heard that some are just like straight bits of pipe?
They are just straight pipes, you can remove them your self as cut them down also, there is a difference in the sc power flare over standard not sure of true gains