Hi
I had a j kerner ac unit on my IVP when I bought it with a P51 type scoop
on   the belly. For speed and asthetics I got flybymike to install their
version of the condenser in the tail and remove the scoop. The results have
been mixed: There has been a very small gain in speed-perhaps 2-3kts. The
cooling on the ground is slightly better. The cooling in climb though is
quite a bit worse. In level flight it's a little worse but adequate. The
asthetics are better but  the cg is farther aft. All in all it's an OK
system. To a prospective purchaser I would reccomend waiting for the climb
cooling to get better. They are working on this.
Bob Evans IVP N4TQ