Plenum and throttlebody

[Gravy69]

In a 2003 GT, if I upgrade the plenum and throttlebody. To a 75mm will I have to get a tune to to show any performancr improvement

 

[Dark04GT]

You will get a mild bump in performance - no tune needed. If you have free tunes you could squeeze maybe a smidge more horsepower (single digit) with an new tune but it isn’t critical to tune it.

 

[Gravy69]

Thanks for the info