Sid,

Mine was installed legally. works great, I have no idea if is slows the plane down, it must but by how much I will never know as I do not plan to ever take it off.

I always wonder how much vac could be created by opening the small side window and adapting a toilet plunger with a hose attached.

Life is a barrel of fun

Ken Andrew
N377SB, '77 112B Hotshot, S/N 526