Builder of high-performance racing boats many of which are suitable for some level of cruising.
A good place to learn about the J/40, its capabilities, and its equipment and maintenance, from owners and published literature. It's easy to contact other owners through this site.
Review of a 40-foot offshore cruiser/racer.
Horner reviews the thinking behind this design, its construction methods, and its history, including pricing history. He identifies design or construction problems that have been found in older boats. Comments include: "Some sailors feel the J/40 set the standard for modern fast cruising sailboats; others will argue that honor goes to Perry's Valiant 40."
Perry comments on the hydrostatics, exterior, interior, and systems of this boat and gives his opinion of its looks and appropriateness for cruising: "When I first looked at this interior, I wondered why two heads are necessary on a 40-foot boat."