Helix throttle body spacer ????

Just wondering how many of you guys out here are runnin these on 5.7 vortec's and if so what do you think of em, gas milage, power, gains or loss...i do have exaust and K&N right now also, if it will help it make a diffrence... Gotta chance to get one for pretty cheap, and want to know if its worth it... :naughty:

I put one on my 00 denali and would not recommend it. I have a K@N fipk on top and it raises the height enough to rub the hood. It also offsets the intake tube which caused the filter adapter to crack. And then the most annoying part is it whistles like a bitch!! It sounds a little like a supercharger but it's not. I can't wait to take it off. Want one cheap??????? I don't think it gave me 2hp or any mpg to be honest.