my bumper is not dirty at all, i don't think my car is to rich with the aem intake, i bought it like this. another thing i think my car is runing too hot could it be to lean. if i get on it for a while a few full boost runs at 21 psi i can see heat waves coming from the hood vent. i live in tx so it can get hot sometimes. i recently started to hear a kncking on my engine that lasts a few minutes after start up, but then goes away, could i have have messed something up or is this normal 4g63 valve knock.

 

11's on pump gas in an EVO8 is a tall order.. see my mod list in the sig

 

depending on your mods, if you change your cams/ etc anything that might afftect how the stock timing affects your engine then yes it is "required" however for simple boltons, it is strongly recommended as it will expose the true gains of the added components.

 

Get a tune. You will be happy you did. No first hand experience, but from what I've read you should get a nice bump in performance.