The F-Type is brought in to compare the 'noise' or exhaust sound. An important area of a car's appeal but all of these vehicles make noise. It is not exactly complex to compare the two cars with V8's in exhaust sound because they happen to both have V8's. If you want to compare exhaust noise compare all the cars as this isn't a best V8 exhaust sound shootout.
The R8 is brought in to compare handling but if you are comparing the F-Type versus the C7 for exhaust sound because they are both V8's why are you comparing the car with all wheel drive and a mid-engine layout to the Corvette for handling? Wouldn't the same line of thinking for the previous comparison apply to have the front engine rear wheel drive V8 car be used? Especially considering it is wet out?
Honestly, the choices and comparisons are rather illogical. Just compare all the cars in each area as picking and choosing one or the other leaves out important context that would otherwise be added. You have four cars so use all four cars in each comparison or what's the point?
Since it is wet out they decide to run the cars from a roll. Finally an intelligent decision in a straight line contest from British reviewers. Yes, eliminate the traction factor when it's wet as some of the cars in the comparison are rear wheel drive. So the 911 and the C7 go at it from a 30 mile per hour roll. The Corvette from a roll decimates the 911. It is surprisingly one sided.
That said the 911's rear engine bias allows it to out brake the C7 from 90 miles per hour. The difference is significant but keep in mind it also is wet out. The rear engine design though shows its weight transfer advantage in braking.
I have listened to the F-Type V8 in person and it is perhaps the best production V8 exhaust note right off the showroom floor I have ever heard. Both sound great and this is very subjective as I have not listened to the C7 exhaust in person but based on the video the F-Type gets the nod. Both simply sound great.
Now the handling test against the R8 does not actually include any hard data. They call it a draw despite saying the R8 was quicker (without backing this up with any data). Yes, this is one of those reasons Autocar comparisons are not that great as it is a string of subjective points. Not that any hard data would have helped that much here since they were running the cars on back roads in the wet. It's amazing this is considered professional journalism.
Despite all those missteps the Corvette is crowned the king of the comparison. It's a hell of a car and can more than hold its own against any of these cars despite having the lowest price tag.