I bought the E85 conversion kit for my 3.7 from Ortiz Performance (OP) for a couple reasons. First, they specialize in the Cyclone whereas a lot of tuners don't want to bother tuning it (...cause what's the point?). Second, I talked via email at great length with one of their tuners, Lee Ament, and he was happy to take all the time I needed answering questions with detailed answers. Because of the amount of service I received before I purchased, I was convinced that I would be in good hands. I also liked that their favored injector (in the kit) is a genuine Ford part (OEM for the GT500).
I could tell right away that the OP gas tune was superior to the canned, Bama tunes I was using previously. I could immediately feel that shifts were taking 1/3 less time to complete and I could feel a lot of throttle boost across all rpm and especially in 1st gear (low rpm). I remember asking Bama to add more throttle boost to my tune and they simply don't make changes like that.
The E85 tune was great. Instant 10%-15% power boost and response across all rpm and really fills in the gap at lower rpm. Feels like I'm using a throttle booster, but I'm not.
There's only so much you can do to a Cyclone without forced-induction and E85 is a welcome, significant improvement if you already have everything else.
Installation is straight-forward, you can find a number of videos on YouTube that show exactly how to do this.
The one important thing to note: These injectors are taller than the stock injectors and
will not fit deep enough into the fuel rail UNLESS you do not use the stock fuel-injector clips!...which is completely OK! OP and all the above-mentioned videos will also state this. You will probably need a spacer (like a washer) on the 4 fuel rail bolts to fill a small gap. (If you don't pull the injector clips, the fuel rail will make contact with the manifold.) It will also run like crap until you put your first OP tune on it.
I recommend this product.