I have a question about tyres, how it was the P0 corsa? And now the PSS how are?
Can tell your impression about the difference about two kind of tyres.
(This is going to be a very long post as I want everybody to understand the Corsas behaviour and results on the car)
The car was far better with the PZero Corsas than with the PZero Rosso´s almost everybody uses in almost all situations but when heavy raining and on-the-limit (or past it) behaviour. But, lets explain it from my point of view, being a racing driver myself.
Our car always ran un Corsas but I´ve tried two more 575Ms with 18" and Rossos and the grip is improved upon them, and as the tire side-wall is more rigid you get a more precise feel of was going on upfront through the steering wheel (more road feel and more feel about the suspension work upfront), a bit louder in what road noise is concerned and when heavy raining you have to reduce the pace because they´re more keen on aquaplanning, but they´re not as critic as PilotSportCups (the natural rival of the Corsas time ago) when raining as they have much more thread and channels to evacuate water than Michelins rival... but on the limit (on a trackday session, for instance) appear two "problems" (lets say) you have to deal with:
1. They are not as progressive as the PilotSportCups are when reaching the grip limit, so they advice with very little margin or don't advice you at all... the Corsas will simply hold the car in its place or slip past the limit, and that´s a bit delicate when you´re pushing hard a 1700kg and 515HP beast (exactly the same happened when I tried a set on my GT3, the grip was total or none with almost no advice, while the SportCups advice they are reaching their limit and when past the limit they´re really sweet, so I went back to the SportCups after a single track-day). With the Traction Control On you will just notice it cuts your gas pedal excesses but with the TC switched off believe me you will slide or spin if you are not really on the matter and really fast correcting. As this car is heavy you will always be carefull enough to brake in the correct point and leave margin for correction, then initiate the turn helping the front end grip (no gas and maybe a bit off regressive braking)... but when the tires are really hot you have to be very gentle (ultra gentle indeed, surgeon footed almost) on the throttle because oversteer will appear without no advice at all and will have to be correct quickly, with very little feedback from the tires, they almost become marble rollers when sliding).
2. More grip means the tires will be harder on the suspension and its true I always felt that the car was grippier and faster that the Rosso-fitted sibblings, but tilted more in-turn and thus was more difficult to manage on the limit... so, it screams for the FHP to be balanced again (tilt less and have masses and inertias under control), as the standard 575M with the 18" and fitted with Rossos is just delicious as it is, a perfectly balanced GT.
So, with Corsas, always in my humild opinion, the car gains... but then demands the FHP suspension enhancement to be able to release all their potential and level things again in track-day use and on the limit and with tyres really burning you have to be very sensible on the gas pedal or have fun sliding the rear with no information at all.
But this "tricky" behaviour and the need for the FHP will just show its face on a track-day session and pushing really really hard with the TC switched off. On-road manners with the Corsas will remain as sweet as with the Rossos, but with extra grip to hold the car while braking, turning or deploying traction exiting a turn always to help you. So for road use, go for them (you will win in all terms but when raining -but then nobody that´s not insane while drive fast with such rollers when wet-), if you are going to attend trackdays and you drive fast but not on the limit they will be perfect, but if you´re able to fully exploit the engine and chassis you´re going to need the FHP to rebalance the car and extract safer the Corsas extra grip on offer... always being sensible with the gas pedal if the TC is off-duty and the tires are really hot.
Wy did my father maintain the Corsas? Because there was no other option for the 575Ms tyre size in 19" until the SS appeared two years ago that Michelin redefined its PilotSport range. Before, you had the PilotSport 2 as the most sporty street focused model and the SportCup as the trackday focused model. Two years ago the brand splitted the range into three models, the PilotSport3 being the first step -a bit less grippy than the previos PS2 but really sporty and only street focused, then the SuperSport going a bit further than the PS2 went to and closer in grip to the old SportCup (if not he same) but with a thread that in wet works wonders, and then the PilotSportCup2, again more capable than the previous SportCup but intended for trackday use only.
Wy did he moved to SS? First because he has just attended about 6 track-days in twelve years of ownership and three years ago he got himself a trackday focused car so the 575 will never enter a circuit again and second because he felt that for using the car as a GT (trips with my mother and almost always in group with couples of friends that also owned sports cars), when it rained heavily, he didn't feel really confident on the Corsas ability to drain water... so he was always keen on changing but there was no other option until the SuperSport appeared.
I had Michelin SS on my Merc for the summer tire set and believe me they are simply the best summer tyres I´ve ever had or tested, fantastic in dry and in also when wet being a sport-car focused wheel (I missed them badly as I now have the winter Vredesteins fitted). In an S-class you will never be able to test a tire to its limits or past them (its an elephant first of all, and its fitted with a ESP so restrictive that fun is simply unknown to that car) but having tried them on 911s I can only tell wonders about them, they are just terrific, they simply tick all the right boxes. Imagine the PS2 ability on wet conditions and the SportCup grip on dry, and as communicative and sweet past the limit as the SportCups are. Its a marvel.
So I suggested him to move to SS when the last Corsa set was due to replacement. And he´s really happy with he results (as I am). The SS will grip in dry exactly as well as the Corsas did, when raining they work far better and the best of all they´re far more communicative (they warn when the limit is close) and progressive (past the limit they´re really sweet to modulate) than the Corsas. So, with the SuperSport you get the best of the Corsas and get rid of the troubles they come with.
This said, I really think the SS are the best deal for a 575M, having the FHP or not, being HGTC or not. If you have it you will be able to exploit the extra abilities and if not you will not sense the lack of if so badly, but always the car will make progress safer as you will be informed were the limit is and make progress on it or past it securely as with the Corsas "I grip and a millisecond later I don't grip without advice" behaviour make the on-the-limit-handling tricky and not safe at all.
Or at least that's my opinion based on track-day use of the car (my father came with me those six times the car entered a circuit and I always had a go in his 575 to leave my GT3 rest a bit) and mountain course sport driving.
So, if you just drive normally and at times a bit spirited and the car is fitted with Rossos, leave them till there is a tire replacement needed but then, no doubt, go for the SS. They cost the same and they´re the best for this car. And if you have Corsas and you have sensed this tricky behaviour Im explaining (hope I was able to explain it correctly) get rid of the Corsas and get the SS straight away.