I've blown the Head Gasket of my Subaru Outback 2.3 back in March 2005.Last few days i've noticed when im backing the car out of the garage it does make a weird vibration & smoke (cloud like smoke) comes out of my exhaust.Then finally last night on my way driving to work noticed temp. gauge went up & up..So l pulled over & rang RACV.Could this mean prob. AGAIN w/ the head gasket???? Pls. help?

head gasket. yup.
Dense, white smoke associated with a sickenenly sweet smell.
Only now, it is bad enough to start fouling out the spark plugs, and cause a misfire condition.
Hope your radiator is not restricted, nor leaks, by the way.

You must mean the 2.5 engine. Yes you probably have issues again, all 96-03 2.5 is are highly prone to head gasket failure. The gaskets have been re-designed several times, you most likely did not get the the newest design in '05 either. The good news is the newest gaskets are working very well when installed properly. The bad (besides the failure) is that you may have damaged your engine by allowing it to run/overheat with failed gaskets.