I have the same problem/ same engine (6 years old)
I believe you will find the leak coming from the
oil sump gasket,about 2 inches above the oil drain
pipe. I pulled the heads to remove the carbon
(reduce compression) and replaced head gaskets.
I am not going to attempt the sump gasket change
however. (looks too tough) I did snug the bolts around the leaking area with a 1/2 in. box end wrench
(slowed it somewhat) Also installed a thin dry
sponge under the oil drain pipe to keep the oil off
of the pulley and belt. I clean after every use.
Good luck!