[AstralWanderer]

One specific suggestion...

Ditch the solar sail (to be plausible, the movement gain needs to be related to the strength and direction of solar wind in a system) and instead consider an "Engine Overdrive" component. This would work by increasing the capacity of existing engines so providing extra movement but at the cost of engine damage (alternatively, give them higher supply consumption to simulate the extra resources needed to keep engines working).

This would provide the option of greater speed but with the downside of needing regular repairs (and the possibility of being caught flat-footed during this time).

This would then create a need for Hardened Engine Systems (Hardened Ion Engine, etc) containing more structure allowing them to be overdriven longer.