"TLER" is supposed to be a simple firmware toggle, changeable at run-time by standard ATA commands. Some drive vendors did it that way, but WD decided to make it a proprietary thing so they could differentiate otherwise identical drives.

Pricing the "TLER-enabled" ones ("RAID edition") at a premium, and then using overly long timeouts (2 minutes??) in the non-TLER versions just to help "encourage" people to pay the premium.

Again, the standards for SATA/ATA always used to mandate a 30-second maximum timeout.. not 2-minutes.

Bastardly marketing, that.