It's not actually that much work, flip the back seats up and unscrew the hooks by the passenger doors. then you'll need to unscrew the rear dome light at the back (unscrew or un snap) after that pull back the plastic to get at two more hidden screws on either side into the ceiling. Once that's all done it's just a matter of snapping it all off! It should only take you 20 mins, 30 tops! Good luck!
go to the Toyota store n ask them if they don't no go on Google and type in this how toinstall rear speakers on a 1991Toyota 4runner
The 2004 Toyota 4Runner has 57.2 in. of rear shoulder room.
The 2003 Toyota 4Runner has 34.7 in. of rear leg room.
The 2007 Toyota 4Runner has 34.6 in. of rear leg room.
The 2004 Toyota 4Runner has 55.3 in. of rear hip room.
The 2003 Toyota 4Runner has 57.2 in. of rear shoulder room.
The 2014 Toyota 4Runner has 32.9 in. of rear leg room.
The 2009 Toyota 4Runner has 34.6 in. of rear leg room.
The 2003 Toyota 4Runner has 39.1 in. of rear head room.
The 2012 Toyota 4Runner has 38.6 in. of rear head room.
The 2007 Toyota 4Runner has 39.1 in. of rear head room.
The 2011 Toyota 4Runner has 38.6 in. of rear head room.