Hi guys, I just got this from CM and I'd like to share what I've found out of these pieces with you. Just a quick and rough review since I've got a lot shit to do then. So sorry for the bad pics with rough description.
Now let's look at what we have.

4 pieces of photo-etched parts, 1 metal transfer. Seems enough for building a well-detailed curbside model. And BTW I don't think these sets are special used for particular manufacturers, I can't see any reason that this can't be used on the revell kit.
Now let's take a close-up look at these pieces one by one to see what benefits can you exactly get from them.
Set A: about 9.7mmX8.7mm thickness: 0.1mm
Parts list:
1. Front grille
2. Sundries bag
3. Badges (cavallino logos, scuderia logos, Ferrari badge, script(only Ferrari, no Pininfarina), they're enough for the requirement)
4. Footrest (only for driver, I can't find the passenger's footrest)
5. Carpet rubber pad
6. Seats control panel
7. Air conditioning and heating system vents
8. Stereo system control panel
9. Paddle shift
10. Sound speakers
11. Radiator nets
12. Pedals
13. F1 gear box control panel
14. Instrument frame
15. Keys and key rings
16. Wipers
17. Air intake and outlet nets
18. Foot guard for driver
19. Luggage belts
20. Brake disks
21. Seatbelt harnesses including catcher
Now let's zoom in
I have to say the guys are really serious, these parts are quite impressive to me. Look at the stereo system CP, you can see the tiny logos, characters are very clear and crisp, but I can also see it's rather a pain to paint it, be patience guys, or you'll go crazy with this... And to my opinion the cover of the CP is designed smarter and more reasonable than KA stuff. The footrest for driver is beautiful with the small cavallino on it. Good eye CM, but I have to say that cavallino should be at least three times smaller than it is... and...where's the one for the passenger?

The instrument frame is also well done with half-etched craft, as well as the seatbelt ring, that's really beautiful and exquisite. One thing that I have to say is the F1 gear box CP. You can see how beautiful it is, but if you apply this on the kit parts, just imagine... The control panel is a solid part with curve with buttons on it, despite you can perfectly fits the curve it will look like a glued-on piece, the fall between the PE part and the kit part will really make you uncomfortable. Do I make any sense? OK but if I were CM I'll do it too lol.

The paddle shift was still not perfect after twice modification. The paddle arms were not so correct and I can see no reason to make the half-etched gaps. There're 3 sound speakers for the dash top and the luggage carrier, very nicely done with beautiful "BOSE" characters. You should modify the kit parts to use the seat control panels but TBH I can't see the benefit to replace the kit parts with them. The buttons are protrudent not a plate.

You can see the attitude of the designer from the tiny cavallino on the heating vent, it'll be even better if the grilles go thinner. The pedals are pure art, simply the real thing, well done CM!!! And you can see the net of the sundries bag. I've never seen anyone else who represented the net so well before, great! CM prevides one bag so you can only do the center installed version. And also you can see the front grille was half-etched to represent the fall of the nets. See the parts 25? Let's talk about this later.

The nets are amazing. All are half-etched, looks really nice in naked eye.

Part 40 was the rubber pad on the carpet, this time right cavallino~

I don't have great reference for the wipers so nothing to say, just look ok, typical CM quality.

I was impressed by the luggage belts. You can see the seams on it, cool stuff really! And the harness can really work. The part 25 I mentioned before were the hoop of the luggage belt. They're really serious on this but... TBH the belts are really not the job for the PE. Here you take a look at the real thing.

To my opinion better provides only the harness. But if you're really bothered to be a needleman you can also get a great result with it. Any way it's beautiful isn't it?
Set A is really impressive and fine with all these serious design and high quality etching. You can get the benefit from it indeed despite the small flaws. And they give you one more set of the brake disk, maybe you can use it for your other projects someday.
Set B: About 4.6mmX2.8mm thickness: 0.15mm
This is just the front grille. Fitness is the name of the game, but haven't tried yet. I did a quick measuring, seems ok.
Set C: About 8mmX7.8mm thickness: 0.15mm
That's for the brake disks. CM's new design could bring more realistic effect of the disks, just making them is a pain...
Set D: About 4.3mmX1.8mm thickness: 0.2mm
Licence plates, only "Ferrari 599GTB".
Metal transfer
I'm guessing this was an uncutted piece, the retail sets may have only 1/3 of what you saw in the picture. Just typical CM stuff with logos mirrors something, great though!
My conclusion is this is a great set which can give your model additional details and realism. Requiring some certain skills and huge patience, but the result will satisfy you indeed. And it's so far the cheapest set you can find for the 599.
PS: mine was a sample set, no instruction contained, they'll give you indeed. And no time so far to check all the fitment, with my experience it'll be just fine.