hmmm mine seems to have a similar issue, giving it the beans down a dual carriageway, high revs in 3rd and 4th then it goes into limp mode. took it to vauxhall yesterday and they ran the diagnostics and said the sensor was faulty (annoyingly i didnt ask which sensor!) they have ordered a new one and will be fitted tuesday lunch time.

the car has turbo back scorpion exhaust but apart from that it is completely standard.