10W 30 should be fine. Check the label. The "type" to put in your vehicle is usually based on climate/elevation of where you live/travel most, but usually I just put 10W 30 in my 93 Legacy and it does fine for Colorado driving conditions.
It is important to keep the right types of fluids in a car, to help it run smoothly. A 1992 Subaru Legacy Wagon DEXRON III for automatic transmission and for manual transmission: GL5 75W90 gear oil.
The 2001 Subaru Legacy has single overhead cam (SOHC).
The 2005 Subaru Legacy has single overhead cam (SOHC).
The 2004 Subaru Legacy has single overhead cam (SOHC).
The 2003 Subaru Legacy has single overhead cam (SOHC).
The 2007 Subaru Legacy has single overhead cam (SOHC).
The 2006 Subaru Legacy has single overhead cam (SOHC).
The 2002 Subaru Legacy has single overhead cam (SOHC).
The 2011 Subaru Legacy has single overhead cam (SOHC).
The 2014 Subaru Legacy has double overhead cam (DOHC).
The 2010 Subaru Legacy has single overhead cam (SOHC).
The 2012 Subaru Legacy has single overhead cam (SOHC).