Hours and hours of hard, rewarding work, if it doesn't drive you crazy or broke first... Be patient it'll take a while to fully absorb all the little quirks about slants, just like any other engine. It seems like I still learn something new about them every day, and I've been fooling around with mine for 10 years.
Best of luck, and let us know if we can help. Slanters tend to be a passionate and loyal bunch, so if you ever feel frustrated or overwhelmed, post here or over on .org and we'll help you through it.
But above all, Resist the Honda... Resist the Honda... :) :) :) :) :)