I found what seems to be a pretty good website for scion parts:
http://www.toyotaparts4u.com/e_catalog/

They have a cruise control option for a 2004 XA for $207.48, which seems reasonable - will that work in my 2005 XA?

thx,
netchic

yeah just that not every part but like exaust etc yeah why not .......

i am not sure if you can buy for engine

check the reviews between 2004 and 2005

All parts from the 2004 xA should work on the 2005....