I read the Edmunds review, it says 7.5 sec 0-60. Maybe you were looking at the First Drive? My 325i manual supposedly does it in around 7.0, but the IS300 feels about the same, don't worry about the numbers, having to shift into 3rd hurts the 0-60 time.
http://www.edmunds.com/edweb/romans/01.lexus.ls.300.rt.html
http://www.edmunds.com/edweb/romans/01.lexus.ls.300.rt.html