Space Combat - Did I miss something?

[Fluffy Bunny Feet]

Concealed manoeuvre drives are contained within ship bulkheads but must be within three metres of the accelerating surface of the ship. Concealed manoeuvre drives add 25% to the tonnage and cost of the drive. The additional tonnage comprises a system that contains and exhausts thruster plate ionisation out of specially designed ports, reducing their detectability to almost nil.

Put a holograph over them or a hull shape shift that exposes them when needed (like the nacelles on a Puddle Jumper).

 

[shirgall]

Gravitic drives still consume a lot power and produce waste heat, just not the same way as a chemical rocket that produces prodigious amounts of mass going out the bell.

 

[Condottiere]

Text implies it gets dissipated.

As regards to holographs or physical external alterations, that might disguise the concealed drives in a visual examination.