Hey guys i'm new to evos, just got mine last saturday. I've been looking around for and intake and exhaust this past week and i read somewhere that its a good idea to get your car tuned after and intake or an exhuast becuase it can mess whith your air fuel ratio. Is this true?

 

yes

Visit the dyno forum for more information on what you can see.

 

To get the most power out of the parts, yes you should tune.
However, if you have the itch to put them on and have some fun you can. Just disconnect the battery for a while and the ECU should be able to handle the difference with fuel trims.