[rismo]

Oil could also be related by leaking gaskets.
Gorgels and pops are by knowledge not a problem, mainly caused by vacuum in the exhaust and part of this engine and will be strengthed by your exhaust. It could be an ignition issue but that would be much louder and you would immediately notice that.

2/2.5 quarts in 7 months is pretty normal for this engine of course depending on the amount of miles. (It drinks oil like vodka)

The oil in the exhaust could also be related to a leaking headgasket, leaking oilfilter housing (gasket) and the gasket of valve cover.

You could take the downpipes of and inspect your turbo's.
Your rev jumps can also be caused by either fuel pump issues or bad sensors which could also cause an abnormal boost build up.

Also incorrect oil could lead to oil / water fumes, as the turbo's require a certain type of oil thickness for sealing.

Do the turbo's make noise (whining)?
So you have only the exhaust as tuned part?
Did you check for codes?
Do you use the correct oil?
Do you notice any oil residu around the engine itself?