1 litre every 200-300 miles is a lot (especially considering the price
of Mobil1).  I recently had my 9-5 suddenly develop a massive leak (went
through around 12 litres of oil in 40 miles) due to one of the flexible
hoses connecting the oil cooler to the engine splitting  - my leak was
very obvious with the engine running oil was spraying out of the split.
Repair was easy, fit a new hose.  Perhaps you have a small leak in this
area?

Your oil is either going through the engine (failing turbo seals sadly
are the most likely) although I would expect signs of smoke or there is
a leak around the engine or leaking out of the engine somewhere and with
your rate of loss, a leak around the engine should be easy to spot.  Any
signs of oil drips on the ground where you park the car?

There is one other possibility, one of the many crankcase ventilation
(PCV) modifications rolled out by Saab was stopped because of high oil
consumption, details here;

http://www.mitt-eget.com/saab/information_ccv_en.shtml

The mod that reputedly caused high oil consumption is the third one on
this web page with a connection from the PCV system to the oil filler
spout - if you have this version of the PCV then modifications to this
may cure the oil consumption.

Hope this helps,

Andy