they tb spacers are not good, at least in my experience, and yes they whistle lol, sound retarded. The lower intake spacer does do a little, not a lot but a little, as to problems with that, i have never experienced any. Anyone had problems with an intake spacer? They work just like carb spacers which have been around forever, so i dont know what could screw up really other than air and fuel, which a tune could solve, anyone know?