I am approaching the 90,000km service on my MPS6 and have been thinking about having the rear diff oil changed as per preventative service suggestions (every 45,000km under certain operating conditions).
Should I go with the oil provided by my local Mazda dealer, or an aftermarket GL5 80W-90 like Nulon/Castrol/Penrite, or Penrite Limslip 90 which is an 80W-90 with more EP additives to bring it to GL6 level and designed for LSD applications?
Does the MPS6 have a mechanical or electronic rear LSD? And do you have any experiences or preferences?