* it is said, that LSU4.9 is more durable during normal conditions

** however, some tuners say that under quite a bit of abuse, LSU4.2 can be more durable

** LSU4.2 is mostly ordered for compatibility (old installs with LSU4.2 connector - perhaps with old fw that would need work to be upgraded and verified/tuned)

** new installs normally use LSU4.9