I'm rocking the Injen Cold Air Intake on my 3.8 and it's been awesome for over 2 years now. Made some really good power. But as RMJones has said it is a bit of a pain in the butt to install and clean. Worth it for the gains though I would say and you only have to clean maybe every 6 months or so.
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