Fitting internal/external electrical cut off.

[interloper]

I'm slowly sorting my car out for sprints and hill climbs (it's an ancient Porker 944 btw). For saftey reasons and to comply with the regs I wish to fit a cut out. I was originaly going to fit two separate cut outs but after looking at what others have done it apears you can fit just one (say an internal one)and then attach a kind to a cable operated remote outside device to it.

Anyone got any good advice they can impart on this matter ?