RB designs has a cylinder head mod that they do. Does anyone know if this is worth it? It's only like $40, plus shipping, so I was wondering if anyone has tried it and what it does to the power. Will I need to rejet? Probably not, I assume. This is the exact thing that the site says about the mod, so tell me what you guys think!: This modification is a great enhancer to all of your performance up grades and will give you an additional boost. I mill the surface and re-cut the squish band. This gives the 200"s more bottom end torque and a snappier rev.