there’s an element of psychology there
That’s where my money is.
Njee, probably true also, but then again the fastest point on my local loop is the corner at the bottom of a hill which it’s quite easy to pedal into at 40mph and it still feels like I’m going to run out of ground clerance before the tyres slip.
My last pair were the GP4000s/black chilli ones, my current ones are the standard GP4000, and while I’m happy to accept that the more expensive version might have been better, the difference is a lot smaller than going from something mid range like the ultra-sport or GP4season to higher end tyres. I think if you were determined to prove that they had more grip then you’d probably draw blood before any meaningfull conclusions.