Yes it includes everything you need. The only other parts you might want to add is a boost and fuel pressure gauge. Also, nothing needs to be modified to make this kit fit. If you want to get a closer look at the install just go to Vortech's site and download their installation manual. The Cobra Killer kit install is basically the same thing except for a few minor changes. As far as headers go: Well that is up to you. You certainly don't need then (I don't have any) but you will likely pick up quite a few more horsepower with them.
Oh I forgot about the driveabilty question... Yes the car drives like stock. It idles smooth, it starts like stock. Everything is just like stock except the power.