I'm running one of those chips in my '95 WRX and am really pleased with it. Mine is set to 1.1bar, but ESL has different versions for STi's/WRX's etc. so it's best to have a chat with them to see what they advise. Also, I'm not sure if they do one for the Version 4....
1.42bar sounds alot to me, has it been mapped in this country? If it was mapped in Japan, there's a strong possibility that the map won't suit UK fuel, unless you're using octane booster?