How can you screw it up?? The cartridge comes out of the box from garret, assembled and balanced. All you do is put your housings on. Jim from J&R (monster-tubro.com) got my cartridge for me. Good friend of mine. He can swap it for ya if you want but it’s really basic. If you need to get a hold of him let me know. The website is old. He’s no longer in Brampton and the number changed.