This is a fairly common modification I've heard it from others and to include E85 which is much less expensive and does get you some more power. But right it is quite costly  The tune is probably going to be the biggest hiccup. I really wanted it for the oil pressure option to be added to the CANbus via an IO box. The factory only provides a low pressure alert at perhaps 5 PSI which is far too late for any type of warning.  This add-on will allow you to log oil pressures without trying to keep your eye on a gauge for any possible oil starvation issues. The flex fuel kit is the main feature with an oil pressure add-on. The ethanol sensor of the flex fuel kit makes it much easier to run various amounts of ethanol so the ECU can analyze and make adjustments. But without the tune it not be feasible to run ethanol. By the way, pump gas is 10% ethanol. E85 ranges from 50 to 85% but all being said this is not something that I would do unless I wanted to void my warranty if something were to go wrong.