The game is crying out for a bigger hauler and the current haulers are balanced badly:
I propose the following:

Lithus mk 1:

Current bonus' intact

Reduce speed by 15%

Increase cargo to 1250U

Lithus mk 2:

Current bonus' intact apart from:

Remove demob bonus

Fast Extractor nexus module performance 1%

Reduce speed by 15%

Increase cargo to 1500U

Scarab mk 1:

Change the scarab slot layout to 4 high 3 low

Change bonus' too:

Masking 5%

Industrial nexus module performance 1%

Velocity nexus module performance 1%

Increase speed to 55

reduce cargo to 270U

Scarab mk 2:

Change bonus' too:

Masking 5%

Industrial nexus module performance 1%

Velocity nexus module performance 1%

Speed increase 2%

Increase speed to 55

reduce cargo to 300U

You make the lithus a slow tanky superhauler with bad slope handling. The Scarab becomes a fast, hard to see paper thin alternative.