I've ran 40% blends in my 1992 celica gt before (2.2L 4 cylinder) and it ran fine. I lost 1-2 mpg in my mixed mileage. The last time I put fuel in it I put in 3 gallons of E85 and the car was on empty, so it's probably 3 gallons E85:1.5 gallons of gas.
It ran fine, started fine, idled fine. Didn't throw any O2 sensor codes. I advanced the base timing a few degrees to give it some more pep.
I also have a Toyota MR2, and most people who want to try running E85, just switch to 550cc injectors, and rely on the overly rich stock tune to get the necessary fuel.