[X] Cruise Nacelles [5.4 Cruise, 6 Max Cruise, 7 Max Warp] [Operating Range: 78ly]
This option is vastly superior to the alternative. If this ship is drag-racing and trying to outrun something, then something's already gone very wrong, and it's not our fault. It should spend most of its time cruising around. If it's near a warzone, it should have at least a couple of escorts. It will never be able to outrun new Klingon warships, they're already deploying warp 8 reactors, at the very best we can stalemate current third-rate threat force designs with reactors a full generation out of date, which aren't and won't be the worst threat to us.
On the other hand, a ship capable of carrying cargo that can sustain warp 5.4 basically indefinitely is extremely attractive. This ship should spend most of its life cruising from location to location, the times it has to red-line the warp drive are exceptions. That extra cruising speed bump will serve to reinforce our entire economy, military and scientific efforts by allowing us to shave precious time on our setup schedules. That means more and better shipyards, military industrial facilities, outposts as well as colonies and science bases. Remember most of the time this ship will serve in the interior of the Federation, and should never be sent onto the frontier unless there's an emergency or there's already ships that have cleared the area, in order to facilitate our setting up outposts or colonies.
If this ship is trying to sprint it's already lost at its intended game. We can compensate for its aggressively mediocre speed by giving it decent phasers, and fore and aft torpedo launchers so a Klingon BoP won't want to try to follow it.