I like that there's research to reduce travel times by 50%, but upgrading a ships engine should also increase the speed at which they transit the system, not just how fast they can accelerate when in a sector.

For example. If I have the default engines on a small ship and the travel time to a place is 10 days, if I upgrade to lvl 2 engines maybe the trip will take 8 days instead? Just a thought. This would give more incentive to actually go through with the (costly) upgrades for ships that you don't personally pilot.