I'm with Dave here, but I did once wish I'd had a spare belt. I got stranded at the Eureka meet when, just outside Branson, my belt shredded.

Today, I carry a crank sensor, RCM and belt. Along with a 1/4" drive E-Torx socket set, six screwdrivers, pliers, metric socket set (5.5 to 15mm), clip leads, DMM, code reader, vise grips, adjustable wrench, sharp knife, wrap-ties, assorted spare fuses (in addition to the spare fuses in the main fuse box) tail-turn-headlight spare bulbs, detail supplies, paper towels, window cleaner, 91% alcohol and convertible top tool.