Finally I have - with the aid of a new chip for my Link and the assistance of Bob Rawle have my WRX performing the best ever.
But I have been thinking in perhaps pushing the envelope just a little bit further by increasing the octane rating of fuel with the addition of an octane booster - NF Octane Booster -racing formula 6.0 Ron.
When tested it actually only achieved an increase of 2.8 Ron but that would give me >100 octane fuel allowing significant advance increase - but keeping boost 1.3 bar max without fear of detonation or increase in charge temperatures.
Have any members experimented with higher octane fuels and increasing advance ?