Syncro: servicing VW 2.1 litre EFI motor

Gday all,
Just wondering about these 3 items below:

1. Plenum Chamber
Definition: A chamber, located between the throttle body and the
runners of an intake manifold, used to distribute the intake charge
evenly and to enhance engine breathing.
Q. Does the motor have 1 or more plenum chambers and do they have water
drain valves that need cleaning?

2. Pollen & Dust Filter
Q. Anyone know what and where this is and does it have a service
replacement part?

3. Ignition timing
I can't find any mark on the pully nor a corresponding mark or scale on
the body of the motor to check ignition timing with a timing light.
Q. Anyone got some thoughts on this and also, can I assume the no.1
cylinder is the same as my 2 litre kombi ... the front cylinder on the
drivers side?
Cheers

Ken
Cheers all

Ken