It should perform better, as long as it's under 20%. If they are using 50% or more, they need to make changes to their fuel system to allow for richer fuel air mixtures. The problem with that is fuel millage will go down, but performance will be fabulous.
That's why it's best to stick to ethanol blends under 20% And if you make the modifications to properly burn 50% or higher blends, you can't burn regular gas anymore. Combined with lower fuel millage, ethanol sucks in that regard.
Variable compression, variable injection engines will perform better with ethanol; ordinary engines will have less power and poorer mileage.