I have a 2005 Mini Cooper S built 10/04 without the LSD. I'm Currently running redline MTL in the trans. I've been reading and it seems that the recommend oil for the 6 speed after a build date of 7/04 is atf fluid? Redline D6 specifically was one of the fluids recommend.

My question is that I do quite a few track days during the summer and I want to ensure I have a proper fluid to protect the trans during these events. Should I keep the redline MTL or swap out with the Redline D6?

 

MTL is necessary for LSD equipped R53 manual trans and D6 recommended for non-LSD R53 boxes.
Can use MTL in non-LSD boxes but would expect maybe 1 mpg less and slightly stiffer action in
very cold weather since it's thicker, but should also afford a little better protection than D6.
I really don't think it would hurt anything as the boxes are the
same except for the differential between LSD and non-LSD.

 

MTL is fine in the non-LSD trans.
WayMotorWorks recommends it and I have had it in my trans for 60,000 miles without a problem (not that this is proof for anyone but me).

MTL is a GL4 which is what a MINI needs.