Official response:
Thank you for taking the time to contact us. I hope that you are enjoying your 2012 Outback.
Subaru of America does not recommend these additives, as we have not tested and approved them for use in our vehicles. If you were to use these or other additives, the warranties on your vehicle would not be voided. However, if they were to cause any issues with your Outback, the repairs may not be covered under warranty.
Thank you, for the opportunity to be of service.
Sincerely,
John J. Mergen
Subaru of America, Inc.
Customer/Dealer Services Department
1-800-SUBARU3 (1-800-782-2783)
Service Request #1-2079047108