13.5:1 compression ratio or Air Fuel ratio?
I've heard of engine with higher compression ratio with E85 then 13.5:1. Stoichiometric Air Fuel ratio is 14.7:1 for petrol and 9.7:1 for E85, hence why you need to use more fuel for a given amount of air, which in turn decreases your fuel economy.
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The key with E85 is the ability to run more ignition advance which generally equates to more power.
This is due to the increased knock/pre ignition propories in E85 which is evident by it's RON/MON number.

Most manufacturers of plastics will give an indication of it's resistance to chemical. Rubber is not very resistant to alcohols/ethanol. For me, the peace of mind that my multi thousand dollar engine rebuild will not be jeperdised by a couple of low $ rubber hose is a good investment.