Check my dyno run after this simple mod

[Carn]

You can try the DF range of octane boosters as well Don. I used them to good effect (but the detriment of my plugs) in the GTI. Gave a healthy reduction in timing pull on successive runs but didn't add much in the way of power gains (2 or 3hp).

Be carefull of any octane boosters that contain xylene and/or toulene, they not exactly plug friendly and can also eat rubber fuel lines if used in too high concentrations