Good immobiliser fitter advice

[Atari Boy]

I need the period correct, but came with one key ‘Vecta’ immobiliser removed and replaced with a new modern version from my 1990 Porsche 911.

Can anyone recommend to me a really good immobiliser fitter, who can correctly remove the old one so it doesn’t fight back and come back into life unexpectedly on a random wet Wednesday when I’m miles from home?

Also, can anyone suggest who are the market leader manufacturers of new immobilisers currently, please?

Thanks,