I was reasearching the xA and the xB too. yes they are a very good buy for the value, but if you want performance dont go here! it uses the same engine as the echo. get a mr-2 or somthing for that money. If you still wana go down this road go here
http://www.scionlife.com/forums/. very good site to get an idea on what aftermarket support the scion has. i believe blitz is or has a turbo for the engine but im not sure. haha well anyways go to the site. its the best scion forum i'v seen so far.