Odd stories. I used M1 in my 400hp Eclipse that saw 400+ timeslips at the strip over 8 seasons,autocrossed a few times a year and M1 never let me down or my turbos;also used it in my Type R which was autocrossed quite a bit and now I use it in my 13 year old 4Runner and it burns a normal amount but never has more than a half quart low after 8000 mile changes which is great for a 174,000 mile vehicle which sees off road regularly.
Maybe I've been lucky but using it with no ill effects since '93 can't be all luck.
'12 Focus Red Candy SE Sport 5 spd
'99 Toyota 4Runner Sport
'11 Subaru WRX STI Hatch