Apple started supporting TRIM ons since 10.6.7 or 10.6.8 if I remember.
The funny thing was only with Apple SSDs, the way to enable this was hex edit the IOAHCIBlockStorage, apple hardcoded the value "APPLE SSD"
Frist was replacing this with the first letters of your SSD but if the ssd were different you, only the one would work.
So the way it works is just replacing the "APPLE SSD" with "000000000" and just is "trim enabler"
With Yosemite if you modify any kext the OS won't start, so this you have to disable kext signing.
Apple as usal.
