The VForce made a significant difference in low/mid performance on my '03 250. You will need the GG manifold as well as the VForce. Also, you should polish the intake where the upper and lower outboard reeds can make contact. This is easiest with the top end removed. Reed life will suffer if they contact the rough casting. I spoke to a Moto Tassinari engineer, and the reed petal can move as much as 9mm without restriction. The clearance in the '03 cases was approx 5mm on my bike, so you can assume contact.