I have a 2006 Mustang GT coupe. Besides the Roush hood scoop, I have Borla axel-backs and a K&N Cold Air Intake. Once I start with the modifications, it becomes an addiction and then it becomes a project that will never technically be considered "done". There's always something else that we want. So here is my question.....What is the least expensive mod that produces the most HP?

 

I've done similar mods to mine and I think a tuner of some sort is the best bang for the buck. I bought mine (Diablosport Predator) from a speedshop on Ebay for around $270. It makes a huge difference.

 

Tuner from either B amacips, Evo or Brenspeed with their custom tune.You will get more for your money as the stock tunes on the tuners (diablosport or SCT) are nothing compared a custom tune. I noticed hardly any gains with the stock tune butwhen I had Doug make a custom tune for me, it felt like a different car!