Without a donor car, the cost will be enormous. This is a very bad idea. Trade cars and get a manual.
Yes, you will need to change the ECU when converting your 1991 Subaru Legacy from an automatic to a manual transmission. The automatic and manual ECUs are programmed differently to manage the transmission functions, so using the correct ECU ensures proper engine performance and transmission compatibility. Additionally, you may need to address wiring and sensor changes associated with the manual transmission installation.
The 2009 Subaru Legacy has a 5-speed manual.
The 2008 Subaru Legacy has a 5-speed manual.
The 2006 Subaru Legacy has a 5-speed manual.
The 2013 Subaru Legacy has a 6-speed manual.
The 2011 Subaru Legacy has a 6-speed manual.
The 2010 Subaru Legacy has a 6-speed manual.
The 2012 Subaru Legacy has a 6-speed manual.
The 2003 Subaru Legacy has a 5-speed manual.
The 2004 Subaru Legacy has a 5-speed manual.
The 2007 Subaru Legacy has a 5-speed manual.
The 2001 Subaru Legacy has a 5-speed manual.