The engine is a 2 liter 4 banger, low to mid-range torque is gonna be hard to come by. I really don't know much about this engine but I would assume that the most torque you'll pull out of it at usable RPMs could come from a supercharger or stroking/boring the engine.
If you put a supercharger on the engine, it would have a good increase in torque and horsepower throughout the entire powerband, but especially more-so at lower RPMs (compared to a turbocharger or N/A mods).
If you were to bore or stroke the engine, you would increase the displacement, so the engine would go from a 2.0 liter to, say, 2.3 liters. If the Focus puts out 159hp and 146tq at 2000cc stock, or 79.5hp/L and 73tq/L, you could assume that another 300ccs would boost those numbers to 183hp and 168tq. Those numbers are definitely just predictions. But still, a theoretical extra 22 ft lbs of torque would be helpful and would most definitely be felt at the low and mid-range.
My advice for right now-- wait for others to lay the foundation for mods and prove the reliability of them.