how good is it?? im tempted to go with it since the apexi kit already has the flange welded on and everything for it...is it decent?? whats it sound like? ill be running about 12-15 psi on the apexi kit

 

From what I can gather they are really good. Most people agree that they aren't loud enough. It doesn't amount to much, but sport compact car tested a bunch of em and the apex was the quickest relief, most efficient, with the least turbine cavitation.