reel spacers how well do they work ?????

they really clean up low end burble , does'nt give any h.p. but it it gives some good thorrottle response a must on 700 and 800 rotax

I've heard that they make the airbox difficult to remove. Any truth to that?

You heard right, I took mine off because I jet too often. Tried all the tricks and finally decided it wasn't worth the hassle.