My tuner reckons I won't gain anything by going to multi-coil ignition, so I'm not going to bother just as an experiment.
Some of the problems people have with E85 are caused by the variable quality of E85. Sometimes the 15% normal fuel in it is rubbish 91 octane, sometimes better. ET Race Fuel sell it with their own 98-octane race fuel making up the extra 15%. Also some tuners don't run it rich enough...