Swapping seats and airbag issues.

[Sidewaze Samm]

Haven't got a problem quite yet - but I'd like to know what to prepare for.
I'm just about to fit manual/heated Msport seats (facelift, '07 reg I think) into a pre-facelift '05 reg E85 already fitted with manual/heated seats.
I know about disconnecting the battery, but will this swapping scenario mean I need an emulator bypass thingy for the airbag? And is an emulator the same as a bypass, or do they solve different problems?
I can't get my head around whether:
- the car will think there is no passenger when there is, so would not deploy the airbag in event of an accident (not good), or
- the car will think there is a passenger when there isn't, so would deploy the airbag when not needed (annoyingly expensive),
and whether the airbag warning light will illuminate all the time, not at all or only when there is/isn't a passenger.
Or indeed whether it's even possible to tell in advance what will happen.

If there will be an issue, do these devices fix it properly, or are they just a workaround?

So what's the best advice regarding what I should expect?

Cheers

And just out of curiosity, would there be any same/different issues if older seats were fitted to a facelift car? Just wondrin'...

 

[Sidewaze Samm]

Have found a 'how to' post that may cover most of my query - will have to see what happens when I fit the seats.
Any helpful pointers still welcome though...

 

[road warrior]

Are you sure the seats will even fit? I have been told the rails are different

 

[mac27040]

all Z4 e85 or e86 have the same rails.

 

[maxman]

When I fitted the m seats in my 05 z4 ,I used an emulater off eBay on the passenger seat and have had no problems with Airbag lights.