I recommend an AEM Cold Air Intake or possibly a nice cat back exhaust system to make some good power for a few hundred dollars. If you wanted to go beyond that you may consider doing some light weight wheels to save some weight and maybe get some suspension work such as lowering springs or coilovers to handle the road better.
2010 Hyundai Genesis Coupe 380GT
M&S Type A Front Grill
KDM 380GT Emblem
Korean Custom Wing Badge Emblem
Injen Cold Air Intake
SuperLux LED Tail Lights
O.Z. Ultraleggera 18x8F/18x9R
E&G Classics Full Aero Kit