One of the things we noticed with the LoPresti WOW Cowl is that after most annuals, the outboard inlet baffles that are designed to provide a smooth path for air to cross the cylinders by lying on the INSIDE of the attached engines baffles is in fact, frequently found to be bent 180 degrees back to the outside. This happens when the plane is un-cowled and re-cowled. I credit Ken with noticing this most often on pre-flight.
We recently met another Twin owner that said in level flight he has to partially open the cowl flaps in order to keep #3/4 cylinder head temps under 400 and asked if we had to do the same. Later we discovered that Twin's baffles were bent as we described above and the pilot observed that it left a large gap for air to escape. Haven't heard yet if that fixed the cooling issue but thought I'd pass along this tip along to other Twin LoPresti WOW Cowl owners.