Most of it will be foam cored carbon fibre/carbon twaron panels. (twaron is a different brand of aramid fibre to kevlar but basically the same) Will be some panels of honeycomb higher up to save weight as well as aluminium inserts and load spreading panels throughout where things need to be bolted into the carbon. eg FIA seat belt anchors through a load spreading plate to stop rip through. All suspension mountings will have large metal load spreading plates to bolt through etc.