Rotella was recommended for a while, because it had the higher doses of ZDDP than the new car oils had. But the new SJ oils have 25% less ZDDP than the older SI oils. SO, there's really no advnatage to use diesel oils any more.
If you have a flat tappet cam, you need to be very concerned about ZDDP levels. If you have a roller cam, don't worry about it. Just use whatever
oil brand makes you happy.
Oil is heated by rpm's. AT normal driving speeds it will be pretty close to coolant temps. As the rpm's climb, so will the
oil temps. FOr the street, with occasional runs to 5K, don't worry about it. On the track, you need to keep an eye on it. If it continually runs above 220*, switch to a good fully
synthetic oil like RP or Redline. (M1 is NOT a true
synthetic)