I emailed Revo to get the skinny on this a few months ago and the answer I got is that you should be running F9. I won't post the whole email here, but this is what Carl from Revo HQ told me;
'The fuel setting wants to be 9 to get the most out of the vehicle due to the fuel pump being a massive limitation on your vehicle.'
To WhiteGTI,
If you are going to change your Revo settings away from the recommended settings to try and squeeze a bit more out of the car, just make sure you do a VAG-COM data log after each change so you can see exactly what the effect of the change is. If you are not doing this, I would suggest not tinkering with the settings and just leave the Revo recommended settings in place, (B6T5F9). This is very important, as you won't be able to tell the effect of the change from the 'seat of your pants', or the engine noise. From my experience the most sensitive parameter is the timing (CF), and it can be affected by changing the boost/fuel without specifically changing your timing setting. Also I would suggest that running at timing 6 is probably a little high unless you are running a very high octane fuel with additives, but again the only way to find out if your ECU is pulling timing (CF value in VAG-COM) is to do a data log run in the car. I found that I was getting more than optimum timing pull, which kills your peak power developed with T6. I've experimented extensively using a lot of different combinations of settings and checking the results in a data log and I've found the safest and best compromise settings are the recommended settings B6T5F9. Just my t'pence worth..
