[ericbsmith]

Another way to get varying levels of system performance is to use the rules for Smaller SM Systems from Spaceships 7 and just install some partial systems. Many systems do have a better performing version; Force Screens have Light & Heavy; FTL Drives have Super FTL Drives; Reactionless Drives have Standard, Hot, Super, and Subwarp. Other systems have non-linear upgrade options; rather than having a "better performing" system you simply switch to a better performing system of a similar type. You might go from a Fission Reactor to a Fusion Reactor to an Antimatter Reactor. Or from a Chemical Rocket to a HEDM Rocket. Or from a Fission Nuclear Thermal Rocket to a Fusion Rocket.