How can i maximize horsepower in my 2013 ford focus SE?

Listen, I have a 2013 ford focus SE with 160 hp stock.Im trying to boost my hp up to improve performance. I have already got a injen cold air intake. I need other ways that arent to hard to do, or exspensive. I don't want to make my car look dumb, so don't say "add a cool loud exhaust and a spoiler." i'm not trying to make a not fast car, totally fast. Just boost the performance.So please, i'm looking for simple things i can do. The injen air intake was 270$ and is said to add 10 HP and boost fuel economy. PICKING BEST ANSWER FOR 10 POINTS.

YOu shoudl write this down and keep it handy Use ONLY AMsoIL or MOBIL ONE 0W-20 engine oil that will maximize power and lower friction. Remove the STOCK plugs which are VERY GOOD, but replace with either BOSCH IRIDIuM or DENSO twin tip plugs. AMsoil is good for 25,000 miles or ONE FULL YEAR between changes. It will keep your CONVERTER and O2 sensors cleaner longer and more.

" is said to add 10 HP "

For an N/A 2.0L engine with the stock tune, It's unlikely you're going to see that kind of gain.

" i'm not trying to make a not fast car, totally fast. "

That's good, because you aren't going to be doing that. At least not cheaply.

For this car, you're not going to make it really fast in a straight line. But you can build on it's strengths. I would put money into tires and suspension, maybe some lighter wheels.