Seconded. I also noticed the lack of 4S versus just 4. But I first called tire rack and these were the alleged Pilot Sport 4Ss they found for me. When you cross-reference Michelin's site, I believe they list this spec under pilot sport 4s. I am leaning towards these being 4S even though tire rack website portrays a difference.
Yeah the foam doesn't seem to have much difference. Not sure my source but I believe it's only 1 decibel, whereas ambient car noise is like 60+ decibels.
When you're spending a few K to get .1 seconds faster, I feel like you might as well throw acoustic foam in there as a requirements.
On the other hand, other people will prioritize tire width for cornering. I'm so busy that I can't see myself going to the track these days (although I've posted otherwise), but in the future when I have more time and money I'll buy some fat tires and/or a roadster 2020. For now I want the braking distance, handling, and acceleration at the edge of the cars performance while keeping a high sidewall without totally killing my range.
Right now I think I'm just going to wait until aero, forged-wheel designs come out from Tesla, fast wheels, and possibly Titan 7.
It would cost me around the same to get the wrong wheel for a few months and then swap to the "right wheel" versus just waiting for the right wheel and jacking up my two sets of OEM 20s tires and wheels. Already bent two rims X_x.