I had a remap done at home for my Astra GSI Turbo (quoted between 20/35 Hp) increase, Once done took it to JBS Tuning in Chesterfield, put it on their rolling road got a print out off the HP, Yes you guessed it nothing, nada, no gains what so ever. Go them back (& my money), put the original map back on and went to Courtnay tuning specialists and got it done right. My advise stick with the specialists. RS/Abbey.