Nothing major, just a crimper from radio shack, maybe a small socket wrench, electrical tape, a flathead and philips head driver. Solder if you're feeling a little more courageous. Basically, you're just running a power wire from the battery to a fuse, the fuse to the tube, from the tube to a grounding point on the car, and then splicing in a couple of wires from the sub to one of the rear speaker wires. The hardest thing will probably just be finding a place to run the wire from the battery through the firewall, and that's not really even that bad. The kit should come with all the hardware installation wires. But if not, then small crimp rings and crimp connectors and heat shrink tubing shouldn't cost you more than $5 total. If it doesn't come with a fuse for inline, then a couple bucks more for the fuse holder and fuse itself. If it doesn't come with wire, the 8 guage wire will run you about $10 - $15, and then inexpensive, smaller gauge wire for the speaker splicing to go into the amplifier part, but I think it does come with all the install accessories you need minus the tools...
[Edited by JTang on 11-20-2000 at 11:39 AM]