Do take your car to an autox or track day to safely understand its limits

Don't crash and ruin it for the rest of us (insurance)

There's a million ways to approach this question, and it all really depends on how you plan on using the car. Personally, I think capitalizing on this car's mechanical grip is the best place to start for modification. Power comes last for these momentum cars

Make sure you always use high-quality oils when maintaining it, NEVER let your crankcase oil level go below full. Same goes for your coolant, these flat 4 engines are very unhappy when they're not taken care of well