As Peter mentioned, the rocker cover is a common source of leaks.

Due to the angle of the engine, the oil has a tendency to run towards the rear and onto the inlet manifold, before spreading to any number of strange places

(partly due to the aerodynamics).

Does the sill around the back of the rocker cover have oil around it?
As can seep slowly so you may barely notice it on the dipstick but, after time, it makes a nice mess of your car and driveway!
The manifolds are fairly robust, although exhaust wrap has been known to cause issues on occasion