Okay, so last post before I do that crazy sleep thing.
In Starmade only RP Servers worry about the fuel, heat and water. but if we look at it from Real Life to get a bigger explosion we don't double the fuel to the explosion, it has to increase according to the inverse square law. In short typically a factor of 4 or 8 for a bigger explosion by 2x.
In starmade to do 2x damage, you just need 2x modules. That never tapers off in any way.
Since all weapons are baselined to 5DPS that means a 1000 DPS cannon just needs to have 200 modules, and to make that cannon do 10x damage you just need 10x module blocks (From 200 blocks to 2000 blocks). You can carry that on till you have energy issues which is currently the only system that slows weapons down.
Now consider that in real life. You said M8 so I am not sure how much modern weapon knowledge you have, but a handgun in 9mm has typically a little bit over 300 ft.lbs of force at its peak (muzzle) and . While the 45 Cal is heavier and has much more gun powder behind it plus the added recoil with about 380 ft.lbs. of force. You might notice in this small scale how extra mass, force and recoil go into only a moderate gain (Now performance wise the two have different factors that come into play). This is why the 9mm is still very popular with military and police, you gain speed, fire rate and reduce mass at the cost of only a moderate amount of force.
That's not exactly how SM should function because inverse square laws and potential energy laws wouldn't be fun in here, but there needs to be a drop off that is higher than shield regen drop off, that way weapons will still trump shields eventually, BUT as ships increase in size the weapons become more costly and less effective. All systems should have diminishing returns IMO.
Why would this work? Because the ship will form a peak performance in the curve. This will encourage more diversity in weapons or at least more batteries of weapons. It also still trumps shields, and gives smaller ships the performance edge, a smaller ship in specific ranges will just function better with respect to energy consumption and DPS per a block. Which makes drones and fighters more deadly. Essentially the end result would be a ship of 5 M blocks would be much less effective than 2 ships of 2.5M blocks. Current system this isn't as much the case unless you can create tons of tiny ships to absorb fire. A current battle assuming that all three of these theory craft ships fire at the same time would end with the big ship over whelming one of the two smaller ships rapidly. Then the firepower of the remaining forces would be half versus a very large ship with its nearly fully intact firepower.
I can get a lot more specific with numbers, but I then tend to make peoples eyes glaze over.