I figured on a higher compression engine it's o.k. to use E10 since it's octane rating is really 94, not 91 ,more modern Holdens like the Alloytec 3 litre V6 run a compression ratio of 11.7:1 and can run 91 RON fuel as they are tuned to that. Getting onto the VL's fuel system, all the hoses are made of rubber, unlike on the VT onwards Commodores which are all nylon tubing, from what I have found out , E10 does deteriorate rubber hose, I have had to use rubber on my VY Commodore when a fitting broke underneath the car, I couldn't get a quote off Holden for the part where the nylon tubing is shrunk onto the metal fuel line underneath the car, I made one out of rubber EFI hose and a quick connect AN6 aluminium fitting & tail. The rubber hose only lasted for a year and was starting to bulge out, the best option is to use Viton hose instead as it is resistant to ethanol based or ethanol fuels. The only part and this is something I probably need to look into as well, the rubber in tank fuel hose is prone to splitting anyway and is the main reason the high pressure fuel pumps fail in the VL's,I found this in a VL tank I cut open, this was caused by a poorly fitted hose, the barbed fitting inside the tank had blobs of solder on it and the hose was just jammed on, this hose eventually worked itself loose so no fuel was getting back to the swirl pot when the fuel level was low. The solution to this is to cut the tank open and replace the hose, you just need to be proficient or take it to someone like a radiator specialist who is proficient to do the job. The reason I mention this is because this is a fire hazard, particularly around the engine bay.