The first question would be, what car and what engine?
Anyway, you've got a 2000 something, so its unlikely you'll get kangarooing with a 57i kit. It is also unproven that the ECU reset does still work with newer ECU's, but it can't hurt. The performance chip would make it completely redundant though. It wouldn't make any difference to whatever you had done to the airbag.
If you have electric windows, you'll have to reprogram them. And also, check the procedure for disabling the alarm, otherwise you may find it a bit noisy when you unplug the battery.
It's a 2000 W plate GSi with an upgraded chip. The dealer swapped 'a chip' out as later models have the air bag disable feature by software.
What I don't know if this is the same chip as what controls the engine ..
Thats better, now I can drool over your car, I mean, give you some accurate info.
Forget kangarooing, I've had my K&N for a few months now, and there's no such thing. I did unplug my battery, and it seemed to make a difference. Don't worry about the ECU losing its airbag bits.
Oh, and a really daft question for you. Have you heard the V6 with an induction kit?? Make sure you can reverse the induction kit fitting, some people can't live with the noise. Personally, I couldn't go back, although the air filter goes back on if its going to Vauxhall.
You will need to put the ignition to II before disconnecting the battery, you can then remove the key but it needs to be back in before you reconnect the battery.