So I now have the Haltech Elite 2500 with the plug and play harness for my IX. I also bought the haltech flex fuel sensor.
my question now before I start to dig in are:

What additional wiring am I going to end up having to do other than wiring in the flex fuel sensor?

The car is currently tuned on a speed density tune coming from a big elevation difference. How safe would it be to use the tune in the car now switched over to the haltech to use to get to the tuner.

Should I remain with speed density or switch back over to a MAF set up with the new Haltech system?

 

I recently went to a Haltech but i have an AEM flex fuel sensor, additional wiring would be up to you, are you going to wire in an oil pressure sensor, fuel pressure sensor. I personally actually got a mil spec harness from OHM racing and rewired everything, added fuel pressure sensor, AEM 5 bar Map Sensor and got myself a Haltech Wideband sensor. Also i am on speed density.

So it all depends on what you want, the base map should be able to get the car started once everything else is stock. Your tuner should be able to provide you with one.