Within the last few months I purchased a 1998 BMW 323is. When I bought it it had 156,000 miles. The car had NO leaks, used NO oil. The previous owner had been using Mobil 1 5w-30. I found out that the 5w-30 is not an approved BMW oil. So...I went to Mobil 1 0w-40 which I understand is a great oil. Something told me at the time I would develop oil leaks if I went to the 0w-40 oil and sure enough, it's leaking around the oil pan gasket. I now have 163,000 miles on the car. I really like Mobil 1 products and the only other ACEA a3 API SJ (I really don't care about the BMW LL (long life requirement, as I change at 5-6k intervals) is their 15w-50 oil. Please give me feedback on this M1 15w-50 for my BMW as well as other oil recommendations. Thanks so much in advance.