When I was racing, I buily my own motors, set up my chassis and suspension, ad nauseum. Since I quit, bikes have become much better and need far less attention to achieve incredible levels of performance. I recommend a school, such as Reg Pridmore's CLASS schools for those with a reasonable budget to Freddie's or Kevin's schools for those with serious dollars to invest on the art of riding before spending any money on your new toy. The only exception to this is a good set of tires. The two things that improve a motorcycle's performance the most are good rubber (easy to buy) and a good rider (much training and practice needed, though most aren't willing to make that investment).
However, tinkering is the American way, and Evan's book is truly a great piece of work. Even if you never tackle any of the projects, you will learn a bundle. As far as I'm concerned, his article on engine break-in is worth the price of admission. Based on his recommendations, my bike was broken in in 82 miles. It is a completely stock 2004 SV650. It runs perfectly, doesn't burn a drop of oil and produced 73.1 HP on a DJ dyno. That's pretty impressive for a stock SV. This book is definitely a "must-read."