I have a 94 gtst and havent had any problems at over 1 bar, the highest ive ever run it was 1.2 bar, after pulling my turbo off it was apparent that it had been rebuilt/reconditioned recently so its not quite as dangerous as doing with the standard turbo
my dyno power curve at 0.9bar is dead straight with constant power gain,
180.3 rwkw with the afr's in the very low 10's
i dont think the standard ecu is as weak as everyone thinks, its probably most of the other systems that stuff/support with it
i think the standard ecu can support 220-230rwkw if everything else is done properly + piggybacks