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I had these fitted all round, on my new CSL reps (went from 18" to 19"). I can't help but think the tyres don't feel as planted as the MPSS' they replaced. I've probably only done several hundred miles, but the feeling I get is they are moving about a fair bit. Traction light is coming on fairly often too.

I imagine they need more air, that's the feeling I'm getting. But they are currently at 32 all round (so 34+ warm), do they really need more?

Interesting as I planned on going for MPSS when the Bridgrstone Potenzas I bought my Z4MC on need replacing, but I guess it'll probably have to be the 4S's now.
Could be worth a try putting more air in, I run mine at 33 front 36 rear.

I know it's different sizes by I ran my 18" 224's at 30/32 and it was perfect. Your pressures sounds high, but if it's right, it's right. And gives me an excuse to go for a blast! I'll up them 2psi at a time and go for a drive.

ETA: Everything I've read about the 4s' say they are hands down better than the MPSS', which is why I went for them. I don't doubt the tyre, just the setup!

I tried 33/36 last night and the car was trying to break traction in 3 on some corners, never happened with the MPSS'. They've done 200+ miles now, should be worn in enough, no?

Probably not, give them some more scrubbing in time and more likely around 500 miles they will have improved.

As you have changed wheel sizes this could be as much about the size/weight of the new wheels as it is the new tyres etc. Are the new wheels much heavier than the old ones? The new tyres are bound to be so this could be a lot of what your feeling. Also a change of wheel tyre size needs a geo check really. Go back to the pressures you ran the old setup at aswell and see if things improve over the next few hundred miles. If your still having issues with the tyres at 500 miles old I would definetly try having the geo checked next.

However I fear most of this is simply down to the bigger/heavier wheel tyre combo and you would have had a similar experience with michelin pss tyres.

I haven't managed to get a geo check done yet. I'm about 400 miles in and the traction light is coming on in 3rd gear on hard acceleration. Something is definitely not right!

My last few sets of MPSS have felt like driving on Ice for the first 50-100 miles, then brilliant there after. Would hope by 200 a set of MP4S would be working.

To be fair give new tires 300 to even 400 miles to break in.

Easily an other 100 miles this weekend and the same. I am going to get to a hunters alignment place this week hopefully (Adam & page are excellent and do a free evaluation, so no cost if it's not that).

Previous experience is that the car, with traction on, will allow a little slip, but it feels like the traction is more aggressive. Or, the car isn't really slipping and the traction is cutting in early/incorrectly.

I can't imagine there is, but a possible reset for changing wheel sizes?

I have heard this on other car forums, apparently they have a softer sidewall then the MPSS so don't feel as good, a fair few people still prefer the MPSS over these especially in the dry.

Try upping the PSI a bit more OP and see if that helps I know it has helped others on these tyres on other forums.

Come on, OP, you know the rule: 'Change only one thing at a time' (otherwise you won't know what's changed).

You've changed many: tyre type, tyre diameter, tyre profiles, tyre pressures, wheel size, all-up wheel weight ...

I'm going for the alignment anyway, it's free if nothing needs doing, if it does, happy to pay. I'm running the PSI that has been suggested, and a few others and get similar. The fronts responded well to 33 over 30 though.

I am trying to do 1 at a time, but I can't put my 18" tyres on my 19" wheels can I!?

Can't imagine it being the tyres themselves. I've just switched to them last week on the rear of the F Type and right out of the box they grip like sh*t on a blanket and a massive improvement over the Pirelli's that it was on. Awesome tyre for general road use (which at £550 the pair they need to be)

Sounds like playing with pressures is the start point