Matty, from years of work with car set up for hillclimbs & other sporty events. don't to big in the size of the bar, 5mm max Why in hillclimbs you need to turn in the bends & still stay flat on the road. when you go to far in thickines wheels lift off the ground in the bend & you need every inch of your tyres to help make the quickest time. If you need space under sump, have, l think there called bush spaces add under the bar. But be careful how much (length of) bush spaces. Good luck & let me now how you went. Bruns