I haven't ever actually tested a station. Propel seems to be pretty consistent.
If you are worried about the E85 concentration, use the Cobb or Delicious Flex-Fuel kits for your tune. They use a GM sensor and can automatically adjust to any concentration of ethanol

 

I previously had every intention to go with a flex fuel setup on my car. Earlier this year I called Cobb and asked why they don't offer a flex fuel kit for the 02-05 2.0L WRX and was told that WRX's for those years only had 16 bit ECU's vs later models (06+) that have 32 bit. They mentioned that the 16 bit ECU doesn't have enough memory to run mapping for a flex fuel setup.

My current setup I'm using an 02 USDM ECU & wiring with an 02 USDM EJ205. I'd love to go flex fuel but I really don't have any interest in updating to a newer ECU and probably have to redo a ton of wiring to get it working.

 

Fixed
https://www.delicioustuning.com/02-05_GD_flexfuel

Have fun stormin the castle

 

^Wow thanks for sharing, really wish I had known about that before... good to know its there though! At ~$600 I'll still plan to go ahead with my dedicated 91 & E85 tunes on the ID1050x injectors. Looking like something I could get around to doing in the spring next year.

 

You will enjoy

What turbo do you have? The E85 makes a bigger turbo come to life

 

Vf34

 

New 91 & E85 tunes from GST

 

Over 300 at the wheels ...Thats a lot of fun right there!