I'd say just leave the headlight in, I really don't think it would be worth the effort. I'd be surprised if you pick up a tenth by just taking it out. If you're not going to run that fast of a time anyway, I would say you're gonna kinda look like a tool going slow with a headlight removed. Just my opinion.
A battery relocation really isn't that hard, but the thick cabling you need can be expensive, and it's kinda tedious to hide the wires. Empty out your trunk once you get to the track, that'll save some weight. You can build a rear seat delete if you take your time and get it right, it will look a lot better and shave off a few pounds. Try not to run on a full tank of gas to save a little weight. Unbolt your front sway bar (I think it's only like four bolts) to help with the weight transfer (see how you like the car after you unbolt it, you can leave the sway bar out if you don't mind how it affects your handling). Get some grippy tires, pref. drag radials with wider rims. That's all I can think of for right now as far as cheap/free mods to improve track times a little bit.