Steering Wheel Change Airbag Issue

[Bod&Hammie]

Hi, my son wants to change the steering wheel on his Yaris Mk1 as it's all manky. He has taken the opputunity to upgrade to a T-Sport model one that has come from a 51 plate and his is a '99 GLS.

The problem is the airbag electric fitting is different.  The only option I can see is to change the whole 4 nut unit that you can see in the picture. I'm not going touch anything without hearing some advice first. I can't see any other options, can you? 

The one on the right is the old GLS one and the other is the T-Sport one.

Any help please.

Thanks,

Bod