Be aware this script (and Trim Enabler) require you to turn off kext signature validation. This feature was added in 10.9 but it only raised warnings on missing or invalid signatures. It didn't actually prevent the kext loading. 10.10 now raises an exception whenever you load an unsigned or invalidly signed kext.
Disabling this check returns you to 10.9-level security and removes barrier to malware installing its own kernel modules.
Yeah, unfortunately there is no way to enable TRIM without turning off signature validation completely. Apple calls the feature kext developer mode. It would be nice to see them providing more fine grained control over which kexts are supposed to run in dev mode — or just enable TRIM for non-Apple SSDs in the first place.
Disabling this check returns you to 10.9-level security and removes barrier to malware installing its own kernel modules.