Great question. I highly recommend you get a spare magneto-coil, maybe an extra CDI, and an NT carb are good investments; each can be had for less than $20 on eBay. Actually, if I knew then what I know now, I'da bought TWO kits; the cost of individual replacement-parts and shipping make it a cheaper and more convenient option for a first-build. There's a lot to learn, but the curve is steep and this newsgroup is a great resource. Having ruined a magneto-coil and needing to wait nearly a week for a replacement is really frustrating. I've learned to avoid problems more effectively, and I keep spare parts (and replace them when used) so as not to be left in a lurch when things break.