One of the most common (and misdiagnosed) M30 oil leaks is from around the larger of two bolts that retains the crank angle sensor bracket. (Bracket shown as No.10, bolt is No.12)
The bolt becomes loose and oil works its way along the bolts thread and out onto the bracket. The oil then drips down onto the crank pulley and is flung off either giving the impression that either timing cover seal is leaking or some other cause etc.
Here is a link re. this leak http://www.koalamotorsport.com/article-m30oilleaks.asp
I had this problem with mine! It's a bit tricky to get to but if you find the bolt is even a little loose then that's most likely your leak! - Good Luck