So, I bought a COBB AP a few days ago, and was going to install it on my 2009 Ralli..

The Ralli has an evo x turbo swap, aftermarket exhaust mani, turbo back exhaust, evo x intake, ams small battery kit, and an upgraded FMIC...

When I go to install the AP, it wants me to flash the ECU to the COBB Stage 0 tune (which is for a stock Ralli).. And also states that an external tune has been performed..

What would happen if I install the AP on my car with the stage 0 tune?

In addition: I spoke with COBB customer support and they told me to ship the AP back to the retailer I purchased it from

 

I'm guessing that you would need a custom map. Cobb would be the best to answer this question though... I would not bother installing the stage 0, it would not be the right map for your car.

 

You would be correct.. I called COBB before I married it and they told me to send it back to the supplier, which I did..

Now I'm back to ground zero, and suppose I need to buy a tactrix cable and a wideband

 

Why not just get a protune ?

 

If you install the AP it will automatically install stage 0 wich is the stock map. If your car was not tune using the AP before and you do not have the AP map save on your computer don't do this.

Is you already have a ECU flash tune stay that route.