In general, Subaru engines are powerful with a lot of torque. But do fuel additives and oil additives provide any benefit? I used to have an Alfa with a 1.7 flat-four and this was ok with these.
I was thinking of trying an injector cleaner. I've used these on my former cars because the kerosene in it cleans the injectors adding a bit of torque and making it more efficient on fuel and increasing responsiveness.
Also, there's an oil additive I've used that was a brilliant non-PTFE type which seriously improved torque and made the engine much more responsive and tight.
Does anyone here use injector cleaner or oil additives on a Subaru flat four engine?