Just found out the 93classic wrx has an ecutek ecu fitted causing the higher boost rate! So will I need to use a high octane booster??And if so which product would suit the best?
I also remove the atmos(pssst) dump valve and put the stock one back on,much better!

 

using shell v power and poss NF octane booster would be best in my opnion, but do a search in the technical area for octane boosters and that should help you..