If its a new car it will be not much, if its an old one the extra it does won't matter becaues you saved on the fuel price. (think about how much extra fuel you can buy for 10K or whatever)
I'm loving the fact right now that with a E85 pegged to 139.9 locally and full octane petrol being about 1.70+ even with the extra consumptions is pretty much cheaper to use E85 now...
just need to sort out the tune though, should be around 15L/100km but getting in the low 20's at the moment.