As for decent modification, my suggestion wud b:
Exterior:
Smoked Head Lamps
Smoked Tail Lights
Side skirts
Original Spoiler
Bumper extensions (not ricer one)
Decent Alloys
Performance wise:
Exhaust muffler with downpiping
Air Intake
Performance spark plugs and wires
Use good Engine Oil
Drive it on petrol and u will chew up any 1000cc car