[X] Dual Nacelles Cruise (+0.2 Cruise)
[X] Dual Nacelles Sprint (+0.2 Sprint)
We do in fact have to keep a budget in mind, with both tactical systems and mission attachments (eg specialized labs, machine shops, expanded medbays, second computer cores, etc) likely to have costly options as well. The quad nacelles only offer a modest improvement for doubling the costly Warp components at the possible expense of core parts of the ship's mission.