Leak on a hose, and smoke, smells like antifreeze

Smoke (blue or black) or steam (white)? White smoke is really steam that is caused by water leaking onto hot surface. Could be leaking from hose running to heater coil under dash, or something else. Check radiator water level to make sure water level is ok. Blue smoke is oil burning. This could be dangerous, caused by similar scenario of oil leaking on a hot surface (from a gasket leak, etc), or exhaust fumes. Black smoke means something is actually burning and could indicate fire. Black or blue some could fill vehicle cabin with toxic fumes, even if you don't smell anything bad.

heater core or one of the hose did you check antifreeze level there could be a leak

The best parts diagrams are found at RealOEM.com
Burning smell in the cabin is usually caused by a leaking valve cover gasket. Oil seeps down from the valve cover onto the exhaust manifold where it burns. Smoke gets drawn into the cabin air intake due to the shape of the car and the air pressure differential between the engine compartment and the heater air plenum.
This will slowly get worse, and breathing that synthetic oil smoke, even at a few parts per million concentration, is probably not good for your kids (if any), so you should get this taken care of.

This is strongly indicative of either a failed cabin heater core or to the coolant lines servicing it, causing a leak. The smoke would therefore be steam. There is no other possible way for antifreeze to get into the vents.

If the smoke really is smoke though and the smell is burning plastic then disconnect the battery negative terminal and get an auto-electrician in to check the situation, as you're at risk of a fire.

To fix the heater is a really labour intensive and fiddly job as virtually the whole dash and crash pad has to come out. If it's an electrical issue then there may be a relatively simple fix, or if the heater blower motor needs replacement then it's almost as major as for replacing the heater core. If you're looking at a professional repair of that magnitude it will likely not make economic sense: depending on the climate they live in some owners just have the heater core permanently disconnected by fitting a bypass to the supply pipes under the hood.

The good news is that there is a Haynes manual for your model which will be of immense help if you wish to save hundreds of pounds/dollars via DIY and there is an active and very useful Saab Owners' Club.

this could just be oil leaking out off value cover and burning off exhaust can u smell the smoke? does it smell like antifreeze ?? if smells like antifreeze more than likely have a coolant leak if has little smell or burning oil smell probably an oil leak

The smoke you could be seeing may be steam, your heater inside the vehicle may have a leak and causing steam to rise out of the vents, if you are smelling the steam this is what I suspect.
Engine vibration could be a number of things, check the engine mounts to start, one of them is probably broken.

White smoke means water/antifreeze entering the combustion chamber(s) or intake passages. Suspect a gasket leak somewhere (tighten all intake manifold nuts and bolts). Check all radiator and heater hoses for leakage and hose condition.

If it smells like antifreeze, your probably looking at a new heater core, just make sure you check hoses going into firewall from engine side to make sure it isn't a leak by end of hose, leaking down into that heater core area inside. If your coolant keeps going down, that's more than likely where it's going.Make sure you check coolant level .

Heater core or one of the hoses are leaking. Low on antifreeze now so no heat.

You have a coolant leak most likely in the heater core. Try disconnecting your heater hoses and coupling them together, then running the engine to see if the leak goes away. If it does, I would have the heater core replaced.