OK, first off, we need some definitions:
SNORKEL : This is an internal duct that takes air from the right cowl intake and directs it to the intake on the horizontal induction. Pic of the Snorkel is:
SCOOP: This is on the bottom of the cowl and is used for the air intake for vertical induction engines.
RAM AIR INTAKE: This is a intake on the front of the cowl, above where the scoop would be. This is used to bypass the weaves the snorkel takes to get air into the engine with less resistance (i.e. to try to get higher MP).
If you are shooting for a IO-360 with horizontal induction, it won't be a problem to get the James Cowl without any extra holes in it. One example of this cowl is on their site:
In the pics you listed, the first plane has a vertical induction engine, therefore requiring the scoop. Mark Manda's plane has a horizontal induction without needed an external scoop (has an internal snorkel).
IF you go with the James Cowl, you are forced to use their Long Cowl with horizontal induction. The implication of this is you will either need a prop extension (Sabre Mfg makes them:
http://www.sabermfg.com/extensions.htm ) or an extended hub c/s prop. I know with the Sabre extension, aerobatics should be limited to either 3-4 G's because the prop is hanging forward more and will undergo more stress. I don't know if the same recommended limitation affects extended hub c/s props.
As far as having your cake and eating it too....Dan Checkoway (
http://www.rvproject.com) had to fabricate his own snorkel. After he was flying, he compared his snorkel MAP to his Ram Air MAP and found __his__ snorkel was super efficient, withing 1/2" of the ram air. His full story is here:
http://www.rvproject.com/20050426.html
Also, be aware there is a waiting list for the James cowl. I have been waiting for my turn since the end of October!