Turbo timers were the in thing in the 90's and early 2000's, but I hardly see them these days - I think people realised there wasn't much point. Unless you switch off right after full load, normal driving will cool the turbo down. By the time I've come off the open road and driven though town to my place, there is not much point in letting it run for another minute or so. I've got a couple of old timers lying around, I don't see the point of fitting them to my current turbo car.