Plugs will foul. Big deal. If you're running E85 and willing to risk it without a wideband, good for you. The money you saved on not covering the base with the wideband will come in handy when you buy new plugs so often.
Keep in mind, Caltex did NOT intend for people to be running this fuel in anything other than a flex fuel taxi. The flex fuel cars have an ethanol content sensor that tells the ECU how much % ethanol there is, and adjusts fuel and ign maps accordingly. Since we don't run this, we need to adjust ourselves. Get a map made on E70, as well as a map made on E85. Watch the WIDEBAND YOU PURCHASED when you drive off from the station. Watch the AFR's and work out in your head (should be simple) what % you just filled up with. Swap map if need be.
Hell, cover ALL bases and have 3 maps made, E70, E77.5, E85.