I pulled the steering wheel off the car, took some dimensions and spent some hours on Autocad and CNC machines. The worst part is replicate the spline.
The spacer is made in 2 parts: female splined aluminium is a "copy" of the steering wheel side and matches the OEM column. The male splined side is steel made and it's a "copy" of the column, and matches the steering wheel.
As you see in the pics, the male and female parts are bolt together: when you fit it you first fit the alu side, then use the stock nut to fix it on the column, then bolt the male splined part on the alu side and cover all with the rubber boot.
You don't need to extend the airbag wires as they're long enough, only a horn cable requires to be extended. You can extend it as in the pic.
After all this, fit the steering wheel on the male splined hub and tight the extra nut.
Extending the airbag wires is not required. But it's not an issue: I did the same job years ago on a Renault Clio Sport and Airbag wires weren't long enough. I simply cutted and extended them and no issues or warning lights came on at the end of the job.
