So I decided to expand my opinion on how V-mods should look like - not a criminal negligence but intentionally cutting corners/downgrading systems that your ship won't need. They should also be somewhat more unique rather then being full d-mod counterparts and maybe not every of them should require dock to apply. Some could actually be designed similar to Repurpoused Fighter Bays from DaRa (which would become vanilla in next update, yay!) - they are to be used on salvaged ships to trade one negative effect from d-mod with something else.
General V-mods:
Light bulkheads - remove some bulkheads or cut holes in them to make it easier to access some of the systems for quicker maintenance. Reduces hull integrity and makes the ship more likely to fall apart in combat but reduces maintenance costs.
Reused armor plates - normally damaged armor plates have to completely replaced with pre-manufactured replacements. Welding the damaged plates together and reusing them would make the repair faster and cheaper but at the price of worser overall armor condition.
Ion thrusters - replace standard chemical thrusters with ion ones. These don't require as much gas to operate but are also weaker. Reduces maintenance cost at the cost of maneuverability.
Stabilized Engine (?) - reduce burn of the ship by 1/2 but also reduce the amount of fuel and supplies consumed by the ship.
Minimized Life Support - the standard operation precedure before entering combat is to depressurize any area that is not neccessary in combat, keeping only the bridge and other important areas stationed by crew pressurized. Doing so and restoring the pressure after combat is time consuming... and might feel expensive when your crew is barely a skeleton crew. Caps the crew capacity at skeleton crew level, reduces maintenance costs.
Carrier V-mods:
Manual fighter assembly - removes ship's built-in speciallized autoforge and assembly automation. Parts are now produced on that civilian shuttle nanoforge and manually modified/assembled by your industrious slaves. Reduced fighter replacement rate, fighters quality and doubles the amount of people required per hangar.
Depressurised hangar - removes blast doors/docking fields from hangar making it easier for fighters to launch, especially with a flight deck damaged. Your deck crew however would doubtly appretiate the fact that they now have to work in space suits and slowly walk around with magnetic boots. Reduces fighter replacement rate recovery but increases replacement fighter deployment speed. Drone wings are less affected.
Phase V-mods:
Shallow dive phase coil: removes phase speed bonus but reduces rate at which PPT runs down.