Ok, I'd like to get to the bottom of this shifty subject:
The double clutch method of shifting applies to no syncro crash box's, of which there are very few in the real world anymore. Big Trucks, tractors, etc. may still have them, but that's about it. We used to teach double clutch downshifting at Skippy Barber back when I taught there ('90 thru '95). In a race car with a dog ring box, it's is even more of a waste of time.
And that, my friends is the heart of the matter:
TIME.
It takes a LOOOOOOOONG time to double clutch downshift, time that you don't have while racing, whatever the venue.
Here is how we used to teach it;
Foot off throttle, apply brakes, clutch in, move shift lever to neutral, with heel of foot blip throttle(while keeping the same pressure on the brake pedal, after all, we are trying to slow down!), move shift lever to desired gear, blip throttle again, release clutch pedal and finish braking/or accelerate thru corner/or spin into the weeds cause this is just to much to do in such a short *^%$#^& time!
Wanna know what my drivers school instructor told me in 1985? Brakes are for stopping. Gas pedal and gears are for going fast. The round thing is for changing direction. Use them wisely!!!
Here is how I shift the FF:
Full throttle, mash the brakes, stuff it in the desired gear, turn the sterring wheel in the proper direction, stomp on throttle, and get the blinkin' hell on to the next turn!
On the plus side, some lucky repair shop will be doing a clutch job on a Vibe at about 15,000 miles! Does PFM do those?