Trivia: The space shuttle Enterprise appears in the title sequence of the show - this shuttle was named after the Enterprise from the original series (after a poll, and also because Star Trek was President Carter's favourite show). A case of reality imitating art and then art imitating that reality.
Trivia: The character of T'Pol was originally going to be T'Pau, the Vulcan high priestess who appears in the original series episode "Amok Time" and in the film Star Trek III: The Search for Spock. Her name was changed because per WGA rules, the scriptwriter who'd written "Amok Time" would have had to be paid a royalty for every episode.
Answer: Warp factor has always been inconsistent and hard to pinpoint, or there's too many episodes that contradict the conversion rates. Changes were made in converting warp factor into actual speed between TOS and TNG. It seems ENT reverted back to using TOS method, which is "warp factor cubed" equals how many times the speed of light they traveled. So warp 4.5 means 91.125 times the speed of light (c). Although in "Broken Bow", with the travels from Earth to Neptune and back in about six minutes means warp 4.5 is about 86*c. However, in "The Expanse" episode, warp 5 was 200*c (instead of 125). 1 ly at 91.125*c is about 4 days, but 100 ly would be 400 days.
Bishop73