I own a 2005 cts with 3.6. Ive heard the 2003 had alot of problems and i believe they have the 3.2 with a timing belt. Some of the problems ive heard and seen are crank sensor going out, water filling up in rear clear cover and popping off when it freezes out, rear pinion seal leaks causing rear diff. to fail. some of these engines burn oil too. since the 3.2 has a timing belt i would change it along with water pump so keep that in mind when u buy a high mileage 3.2 engine. Its a beautiful car just not the most reliable car for the money.