Sensors

[jimbob55]

For combat sensors, only one component will give a bouns to hit in combat.

For multiplex tracking, I don't know if they are additive but you are paying in metals for each target you can track + hullspace for each component you mount. Best to mount the highest level available and only mount 1.

For long range scanners, they aren't additive for the range, so 1 at highest level is best.

For the sensor grids (tachyon, graviton, psionic etc) I don't think they're additive. You will only be able to see stealthy units with lower cloak values than your best scanner. Again mount the highest rating that you can.

Tachyon sensor 3 costs 2500 metals and 1100 radioactives and gives level 4 EM active.
All the rest at level 3 cost 1500 and 500 respectively and gives level 4 scanning ability. Bearing in mind that all cloaking has equal values for all scanner types at the moment, any scanner will do the job. Pick the one that is on the branch of the tech tree you are closest to.