I'm not trying to knock you or put you down mate, just passing on experience.
I was in your exact position 4 & 1/2 years ago, with a massive st2 spec car and a custom map. I was absolutely confident I'd see 250bhp, I knew I would, I had to, it was the best spec going.....
then it made 238bhp. I was GUTTED, until I drove it, and realised it was quicker than i ever expected 250bhp to be.
That turbo lasted 3 days. Another went on, and it made 240bhp/290lbft. A year later is was 230bhp. another year later is was 220bhp, then after 4 years it was 208bhp / 262lbft. Nothing else changed in that time, it just lost power every year, and got slower and slower. When the turbo came off it was absolutely ruined. No ebay rebuild kit can fix cracks in the hotside you can see daylight through, or score marks on the comp housing caused by the comp wheel from a dying thrust bearing....
250bhp numbers have indeed been proven several times, but who's to say any of these lasted. perhaps some did last 2 years, and the owners did 2000 miles a year? if you do 2000 miles a month like I did, that same turbo may only last 8 weeks!
250bhp ko3S plots sometimes offer WORSE characteristics than a 235bhp plot, because so much heat has been produced with a massive spike to get the torque (and subsequently power) up low down that they run out of steam sooner than a less stressed setup. Thermal protection mapping due to modelled EGT's can kick in and kills top end power stone dead.
So, like I say, I'd stop worrying about figures and think more about how it drives, an R-tech st2 car with a forge actuator is a very punchy motor indeed, the actuator helps the turbo hold onto boost and makes for a really quick car
