Michael Foster

If it's any help, I bought a chip from a German company called racechip+for £200 ,just plug the wiring harness into your car at 4 points ,follow diagram, took 10 minutes, my gtc has 170bhp now instead of 140 bhp ,they also do one that would have given me 235 bhp mine has been in 3 years now ,you also get an app for your phone so you can connect to the chip by Bluetooth and change the settings of the chip

I would check window seal,you can buy a tube cheaply from your local accessory shop

Not 197k ,not even if its a diesel

if your astra is the model with a tripometer button in the clocks ,put your foot on the brake and push the tripometer button at the same time turn on ignition ,wait 10 seconds and the numbers will begin to flash then 0000 .turn off ignition then back on ,should be reset. If not its done by accessing the menu on the left stalk