depends on the model, if you have the more expensive model with the 2 tweeters and the low end speaker in the back you will have all 4inch. but if you have the cheaper model it will be 6 1/2in and 5 1/4in. take off door panel before you buy and find out. http://www.YouTube.com/watch?v=zImCMtrBl5Q (video covers 96-99 avalon)
Both the front and rear are 4" door speakers, although it is not unheard of to fit 5.25" speakers in the front, and 6" in the back. Hope this helps!
All the door speakers are 4' in size for replacement.
Struts in the front, shocks in the rear.
The 2010 Toyota Avalon has 56.2 in. of rear hip room.
The 2011 Toyota Avalon has 56.2 in. of rear hip room.
The 2007 Toyota Avalon has 37.5 in. of rear head room.
The 2013 Toyota Avalon has 39.2 in. of rear leg room.
The 2006 Toyota Avalon has 37.5 in. of rear head room.
The 2008 Toyota Avalon has 56.2 in. of rear hip room.
The 2010 Toyota Avalon has 37.5 in. of rear head room.
The 2006 Toyota Avalon has 56.2 in. of rear hip room.
The 2003 Toyota Avalon has 55.1 in. of rear hip room.