These results aren't bad, but honestly there is probably some room for improvement. M1, especially in this grade, is known for high iron wear - it is the oil upon which Valvoline bases their claim that their own synthetic give 4x better wear protection. The lead is also a little bit higher than I think you could do. I'm not particularly familiar with this engine, and maybe nobody here is, but it will probably last much longer at this wear rate than you will likely keep it. Still, if you wanted to get the best results possible, I'd put money down that a change to any number of different oils would prove beneficial. In the "synthetic" world, you could look at Valvoline synth or Valvoline Maxlife synth, or Pennzoil Platinum, or if you wanted to go the the trouble, something like Amsoil SSO. Even some other oils in the Mobil 1 line might be better, such as 0W-30 or even the 5W-40 TDT, despite its heavier grade. In fact, I wouldn't hesitate to run the TDT and I think it would give you excellent results.
I think any of the oils I've mentioned would be good for 10k mile intervals. The Amsoil SSO and possibly the M1 TDT could likely go considerably longer. Either approach would likely at least keep the cost per mile level while improving your overall results.
