At your hieght and weight you would fit better on the 450 and it will more likely do exactly what you want. You will want to regear both as soon as you get one or the other. The gearing on the 400 is a little high for the bottom 3 and the 450 is just a tad too low. I have been to several national races where the suzuki 450's FI leans out and hot seizes the motor. Some how the fuel mapping gets out of wack in over rev conditions. The same system is applied on their 400. I havent heard of any problems with the Kawie FI except with the vapor locking fuel pumps due to the tank design but I'm pretty sure they work the kinks out of it.