Where to make the Manifold Cuts
 

Before you install the GReddy Manifold, you need to make stress relief cuts in it. This is where you make them (Thank you JimB-15psi.com for the picture).
http://jeffwittrig.com/images/GReddy_Manifold_cuts.jpg

a sawzall with a metallic blade works well, but you'll tear up about 3 blades doing it.
Don't forget to plug the holes with rags, you don't want metal shavings blowing through your turbine when you fire it up.