The first part of your post is spot on. The second part not so much. Everyone at the track that switches from race fuel to E85 does not change anything in combo except carb and or tune if EFI. They still use same carb just get set up to run E85. I'm thinking of going E85.
What C/R are they running? E85 starts to get efficient at around 14:1 static compression ratio, depending upon ignition tuning and blah blah blah, for NA. Compression Ratio for boost is less of a concern as you just adjust it by adding more or less PSI. I've read quite a few articles where the E85 engine compression ratio worked best anywhere from 13.5 up to 16. Just all depends on the engine and cam and tuning and rpm range and and and.
Regular Gasoline starts having issues around 11:1 C/R. That's why on the high-comp gas motors you start seeing 115 race fuel, fuel chillers, ice-packs on the intake, etc etc. All to lower the charge temp and prevent detonation. You also don't see too many gas motors running much above 12:1 as the fuel gets pretty boutique and expensive.
Also, to anyone watching, notice I said nothing about MPG going up, just power. E85, pound for pound, has less thermal energy then Gasoline. That means your overall efficiency will be less, giving less MPG. Nitromethane is the same way. The reason you will get more power with a properly setup engine is due to the optimal conditions under which E85 should be combusted. A higher compression ratio means more torque. A cooler burn means more timing advance for a longer power cycle. The evaporative nature of alcohol means you get a cooling effect from the intake charge which prevents detonation while also giving a better mixing of fuel and air.
You have the potential to see more power with a purpose-built E85 engine over gas, but you will never see better MPG in comparable engines. If you are talking race engines, the cost for E85 is MUCH MUCH better then the cost of 110-octane gas drums and also much more forgiving to bad tunes. I've read up on a few guys who converted their high-comp blower setups to run E85 and noticed a marginal increase in performance. Here's on website on some guys who did that:
http://www.raceone85.com/
That is assuming you have an E85 pump anywhere near you. Where I live we don't have one. Just E10 in all the pumps. Not that it really matters for me, my interest in building a 1000-hp drag car has faded. I like turning too much now
