Did an extended test drive this week with the new Cayman S. Stock suspension (no PASM), PDK, no Sport Chrono. A few quick impressions.
1. Very beautiful
2. Great fit and finish
3. More trunk space than I thought
4. Excellent driving position
5. Brake and throttle pedals too far apart for proper heel-toe, unless they are closer together in the 6MT, which would be unlikely, right?
6. Engine not even close to M3 in sound, eagerness to rev or flexibility
Not as good, but different and I do like it!
7. Electric power steering really is as bad as the reviews state. More on-center play than in M3, and less feel and feedback. Certainly way worse than the previous Porsche HPS system. A real shame.
Hmm..tbh I didn't think it was that bad 
8. The car is slow. If you think the M3 has "no torque," which is debatable anyway, you will hate the Cayman S.
I'm not sure why you are saying this. The tq is pretty close to the M and it is a lot lighter..I thought it was a pretty good amount, although there could be more
9. Fantastic cornering, no brake dive, super high limits. BUT you have do drive through the weird filtered steering software which spoils it for me.
Not sure what you mean..are you talking about the paddles?
10. OK brakes
11. Really don't care for the PDK. Buttons on the wheel are strangely set up. There is a button at 3 o'clock and at 9 o'clock, but they both function identically, for drivers who are right handed or left handed. Push with your thumb to upshift, and push from BEHIND the wheel with your index to downshift. Not a great design. Give me a real column mounted paddle shifter.
A 'real' steering wheel is offered, definitely recommend it. Actually HATED the one with the shifters you are talking about
12. The PDK seems to be designed to coast when you lift off, even in full manual mode in a low gear. I lifted in 2nd and 3rd, and instead of the expected "engine braking" the car just coasted. Not normal.
This is a feature you can turn off
13. I'll take the 6 spd, but if you get Sport Chrono, I believe you cannot de-activate the automatic rev-matching on downshifts. Not good if you like to double-clutch, like I do.
14. When I got back into my E90 with Dinan mods: intake, exhaust, diff, pulley, Stg III suspension, software, strut brace, toe links and monoballs, it was clear I had a superior car for me. I expected to fall in love with the Cayman before the test drive. Afterward, the M3 sounded way better, the engine is a killer, the HPS was better, and the 6MT was better than the PDK, although not better of course than a manual Porsche. Also significantly more power and torque.
You are comparing a modded car to a stock one so I would have to agree with you thinking a modded M3 as yours could feel better than a stock porsche.
15. Oh yeah, the ride in the Cayman is choppy with its short wheelbase compared to the M3, and can't match the suppleness of the stock M3 suspension. And it certainly can't match the combination of cornering and smoothness of the Dinan Stg III.
Not as smooth, but still decent
16. But it's a light lighter and of course will do better on the track.
17. The M3 is overall more versatile, in that it will do almost as well on the track and better as a DD.
18. If you want a Cayman S, get a used earlier version with the HPS and 6MT
I will have to disagree with you here. The new generation is such an improvement over the older one..why did you favor the 987 to the 981?