You can update your handling with sway bars, frame connectors, struts, shocks, springs, etc. Improving handling is always a good performance route to take. As far as the performance mods, anything more than a good axle back kit, a tuner is required to achieve the desired gains safely. Modifications to the air intake or headers and x-pipes can cause lean conditions as well as check engine conditions. Gears also require the tuner to correct the speedometer as well as shift points on the automatic transmission Mustang.