Last i jeard uprev is the best tune you can get. However i see you have an early car. You might not be able to find an off the shelf tuner for your car.

 

Since you have an 03.5 you should be alright, but some of the early sedans are not tuneable with uprev. Only way to know is to physically check your ECU and see which one you have. Black is good

 

So noob question here but the only reason I ask is cuz I've never needed to look where's the ecu for the sedans. Someone told me under the passenger seat but to get to it you have to pull the carpet up. And I don't want to mess with my interior if I really don't have to. Anyone know?

 

Its behind the kick panel on the passenger sidewall. Below the glove box down by the floor.