Im looking to add a 1/2 inch plenum spacer to my setup that I have right now. Question is will I need a retune by adding the spacer? Reason I want to add the spacer is I have the Mrev lower plenum but current am running no spacer, and since its a revup I figured adding a spacer in with the Mrev would gain some more power. My assumptions right? Since its boosted now I have no Idea if the spacer makes any difference or not.

 

I would get a retune if you put a spacer on... Personally, I wouldn't spend the money for a spacer.

 

Knowing where you are headed with your Z, if a re-tune is necessary, I would just wait and do multiple things at once. Unless the HP gain is fairly significant to justify the cost of the re-tune.

Happy Thanksgiving Homie!!