Only time I have had a car with oil leaking problem was due to worn/torn rubber on the screw that holds the oil in. Replaced it and no more leakage.

I switched my SVT couple years ago and haven't seen any problems. Goes 5k miles without any noticeable drop in oil level.

98.5 Contour SVT "Too many OB/GYNs aren't able to practice their love with women all across this country" --US President George W Bush