I can help solve this mystery.
I've been through many sets of Pirelli's and Michelin's over the past 15 years on my Vipers (all gen's). I've had the opportunity to test many, many tires myself and have also had the privelege with discussion this subject in details with SRT engineers and a couple tire manufacturers. I know for a fact that the Michelin's are a better tire for the Viper, not just by it's design, but also by it's compound.
Dave666 mentioned he was being steered toward Pirelli's, but I'd be cautious. Speak with those who have owned them, and especially if they tracked them.
My experience. The Pirelli's scrub away much quicker AND take longer to heat up. The lateral grip of the tire is less than the Michelin's. Also make note that right now, in 19's (not only is there a backorder of Pirelli - which is common) but the UTQG of the Front vs rears is different if buying (what I assume you'll go with Rosso) is 220 Front/140 Rear. Keep an eye on it depending on the size you need, you may not have a choice with it.
Aside from the tire itself, be careful getting into too short a sidewall, this is what you'll have with the Pirelli's (especially the rear - and especially if you plan on 20's). Yes the Pirelli looks good on the rear wheel, because it comes in a 355. Great for looks, but adds up to worse performance, and it's significant. Keep in mind your tire is part of your suspension, that sidewall does more than take up space. The shorter sidewall is nice, but...
Hands down, the Michelin is DEFINITELY a great tire. Yes stay away from the run flats, and make SURE you get the OE Michelin tires. There are identical sizes for the Michelin PS/2's in a "non-viper" tire, one is a "Viper OE" the other is not. Look for the letters "C1" on the sidewall, that's the "Viper Michelin" - don't just look at the size. You'd be surprised how many Vipers get new tires and don't have the Viper PS/2 on it. It actually has a different compound in it. Just look for the C1.
Last note on Pirelli's. A few sets ago, I needed new tires at the track. Tire rack had them in stock so I literally sped down there to have a new set put on and sped back to the track. I didn't heat cycle them properly, just drove 100 miles and put it back out on the track. The rear tires began to chunk out, little bits of it were coming off the tire. There went $1100, the tire was out of balance with no hope of gettnig them in spec. I've done this many times with the Michelin's and never had an issue. Fast forward a year later on a new set of Pirelli's (again PZero Rosso). This just happened this weekend at a track event at Autobahn... The Inside rear tire blew out during a sweeper. It let go on the inside sidewall. Barely saved the car (but I think I soiled myself), almost hit the gaurdrail. That's gonna be it for Pirelli's for me. I was a die hard Pirelli fan, but switching between the two, I've truly tested them. I'm tired of the back ordering, UTQG mismatch in Viper sizes, low sidewalls, and harder compound. I usually don't have a strong opinion unless I'm sure of it, in this case... I've stayed in Pirelli too long as it was.
I agree with most of the gang who have posted here. The PS/2's are excellent. As Jon B said, you rarely hear a mixed review of the new PS/2's. It's one of the hottest tires out there.
And for those who care, as always, Jon reacted quickly and I have a new set of Forgeline's ont eh way, with MICHELIN meat on them. Thanks Jon for always being supportive, sharing that knowledge, and reacting quickly. Don't reinvent the wheel, go with the guy who has the most knowledge, most people buy from, and just happens to have the best prices (I'm not kidding, he was cheaper than tire rack).
Hope this helps.
