There's a few stats about the Fusion fuel currently that are a little...disappointing.

Considering:
- It's an endgame fuel, requiring considerable expense in terms of time and research.
- It uses a fluid ingredient, thus restricting it from guaranteed quality recipe setting.
- Uses moderately expensive ingredients.
- Stores only 2.5GJ out of 41.21GJ of energy sunk into it.

I'd propose the following stat changes.

• Fuel Value: 2.5GJ --> 6.156GJ

Nuclear Fuel (1.21GJ) as an example:
Made up of 1x U-235 (around 8GJ in a Uranium Fuel Cell) + 0.1GJ of Rocket fuel. 
This only uses 14.938% of total fuel energy in.

Perhaps the jump from Nuclear Fuel to Fusion Fuel (add 40GJ of Fusion cell) could be similar:
1 Fusion fuel, made up of 1x Fusion cell (40GJ) + 1 Fusion fuel (1.21GJ)
41.21 x 0.14938 = 6.156GJ

That is if you want to keep the same (in)efficiency of scale.

• Vehicle Acceleration: 300% --> 325%

From [anything] to Solid Fuel = +20% = 120%
From Solid Fuel to Rocket Fuel = +60% = 180%
From Rocket Fuel to Nuclear Fuel = +70% = 250%

Its a rapidly plateauing increase in acceleration, some napkin math would show...
From Nuclear Fuel to Fusion Fuel = +75% = 325%.
But considering its *Fusion Fuel*, perhaps even higher would be acceptable.

• Vehicle Top Speed. 120% --> 150%

[] --> SF = +5% = 105%
SF --> RF = +10% = 115%
RF --> NF = + 0% = 115% 

No real pattern, so this would have to be a slightly better reward than just 5%.

Ingredient-wise it seems pretty balanced, no complaints there.

This feedback makes sense! When I get a chance later today I think I'll implement most of this, though I'm unsure about the huge jump in top speed, since max quality fusion fuel would then be 225% top speed which seems maybe too wild compared to nuclear fuel's max quality 137.5%. Maybe having fusion's top speed at 130% or 140% at most?
Vehicle Acceleration I might make 350%, I'm a sucker for nice even numbers.
Fuel Value can definitely get a buff too, the only consideration I had when I chose the number was that I was a little upset that the stack size buff to rocket fuel meant nuclear fuel had a smaller fuel value per stack, I didn't even consider the energy value of the fusion cell when I set it, maybe 6 or 7.5GJ?
Thank you so much for the feedback!