I have an 06 GS300
There are 2 intakes (that i know of at least) made specifically for this car.

1. Fujita SR-2402 2006 Lexus GS300 Air Intake
http://www.frsport.com/Fujita-SR-240...ke_p_9202.html

2. Lexus GS HKS Premium Suction Air Intake Kit - 70018-AT002
http://www.streetbeatcustoms.com/HKS..._AT002/807008/

Which intake is better? how are these two intakes different? and which one is better? (I have an HKS Hi-Power exhaust already)

 

OEM Intake, it's not as shiny but it does exactly the same thing. Intakes have never done a thing for any of the cars that I got suckered into putting them onto except make them noisier.

 

I agree. I think the only intake mod worth doing is increase the ram air effect with an intake funnel, and keeping it cool. Are there GS kits for this?
Exposed pod filters are not the way to go for cool intake air.