I have a 1999 Olds Silhoette with a bad 3.4L engine, and found a 2001 3.4L engine with only 63,000Km on it for an attractive price. I've heard that the intake manifold was changed on the 2002 engine, but that the 2001 engine should be a direct replacement. Does anyone out there know what problems I might encounter putting a 2001 3.4 into a 1999 Silhoette?