hi there
i had a bad leak on my 99 RR not that long ago - a drip just to the inside of the offside wheel. turned out it was the oil cooler had split and was pumping out oil when the car was being driven and leaking so that when i parked the car it would drip down onto the road. although strippped down the front of the car - took off intercoller, grill etc and left the oil cooler sitting angled down - it never leaked overnight at all - it was then that i figured out it was only coming out when the engine was running. so replaced that and the cooler pipes and it has been fine ever since.
cheers