my brothers pulser got dyno'd at Power station and got 256bhp@fly at 1 bar
That figure is VERY low for 1bar. I would suggest it's your brother who got the inaccurate figure. The average 1bar Pulsar is around the 280bhp mark, even with the top mount ic.
The 309bhp figure would be possible at 1.1bar, but only with a front mount intercooler. The top mount would be around the high 290's
Cheers