I have 99 GS 400 stock, I am looking for a little more out her. Yes aren't we all haha. Should I put a cold air intake and any other ideas.

 

People usually start with intake, headers and exhaust as power adders. Then other drivetrain bolt-on items such as a high stall torque converter (precision industries) and a steeper geared rear diff (3.73 LSD from a mid 90's Supra). These items will make the car completely night and day. But not cheap for all this stuff. Good luck.