It's great to see Swamp and Bruce in agreement.
OK swamp & Bruce first, the 8 seconds Bruce is talking about I believe referred to semi-race compound against PS2 which I very much doubt will yield that kind of improvement unless the suspension is retuned to take advantage of the extra grip available, plain and simple.
Now what malter2.0 is talking about might improve the car's ability to take the corner as quickly as the tyres would on their own though I would be less sure of this. To me suspension and weight balance makes more of a difference to confidence and thus lap times than anything else, of course all other things remaining equal.
But as always we are miles off topic and should get back to the discussion in hand.