to use E-85 make sure your injecters seal , fuel pump,,rubber hoses in otherwords the stock crossfire can only ( safely ) run e- 85
at 40 to 50 % due to seals and rubber ,, I have run 45% with no problems,, also research all you can on running e 85, friends have 100% e85 in their srt-4 mustang, and hemi charger,, with no problems, they told me about once a month they get the tank as low as they can and they use 100 oct gas.
so go for it,,, just in case you are interested i am working on a 3.90 diff for the crossfire the problem right now is a wavetrac for them we have two going into crossfires soon,, would love to install one into a limited ,,, it would be like adding 45 to 55 HP

look for your vin here SRT6 Serial Numbers ~ PDF format file...continued