something to remember boost gauges are rarely spot on when apt tuned mine they installed their own nomad boost gauge along with mine and theirs was reading 2-3psi more than my cheap and chearfull 30 quid one!, so u could be running more boost than u think and hitting the 10psi limit, also your ecu will get the boost pressure quicker than your boost gauge will read it, had the same problem with mine when mine was standard, set mine to 8 psi still cut out, i know now why coz it was really running 10psi!

pick up a chipped ecu and it will be fine