I think the all-time fastest throttle cable replacement I've seen was on an original Speedster and done by Porsche Mechanic extraordinaire, Rainer Cooney, at an event at Watkins Glen on the side of the road.
He had a spare cable in his frunk, a pair of pliers with a wire cutter, a 2"-ish long piece of shrink tube that just fit over the cable OD, along with a tube of "Dyna-Lube" and a BIC cigarette lighter from his spares.
He got in near the accelerator pedal, cut the end off of the throttle cable at the pedal with the wire cutter, slipped the shrink tube over the cable and then inserted the engine end of the spare cable into the other end of the shrink tube so they were about even and shrunk it with the lighter.
Then he told the car's owner to slowly pull the old cable through from the engine end and he lubed the new one as it was going in. Slipped the pedal end into the hole of the pedal when he still had a big loop before the cable was fully pulled through (the pedal end is a "Z" bend) and then went back and attached it at the linkage end.
He was almost done in the time it took to read this post. I was very impressed and when I got home I added a piece of shrink tube to my spare cable and threw a BIC lighter into my tool bag.
Pretty slick, huh? Just food for thought, Replica-istas.
Never get caught on the side of the road by a frayed/snapped throttle cable!!