PPP will always fetch a premium, a later standard car will be one of thousands and no matter how much you try to make it a wannabe PPP C63 it will just be another aftermarket modified c63 which i and many others would never touch.
A 2012 m156 is pretty much bulletproof i have one from new and never required a warranty.
A PPP might be worth more in the future but you pay more for it initially so it doesn't really matter. All you're really getting that you can't easily replicate is some forged engine internals. That would be nice but it's not needed to support the standard 500+bhp these engines make when unrestricted.
The PPP or standard discs are interchangeable as the PPP calipers are the same as standard just painted red. The steering wheel can be retrimmed to your taste for less than £200 and most cars don't have the LSD.
Personally, I didn't see the point of paying the premium when I've ended up with something which as at least as good if not better. Remap, Wavetrac differential and Brembo fully floating 2 piece discs for £2,500.
By all means buy a PPP if the price is right but equally don't dismiss other cars if they're not because what you actually get isn't much more than standard.
As for warranty, yes the C63 is relatively bulletproof. However, since I got mine in 2017 with the 2 year AMG warranty I've had the following done:
- Electrical gremlins with the safety restraint system, so new control module.
- Further electrical gremlins with the same thing, turned out to be wires trapped in the seat mechanism which had been incorrectly installed at the factory and finally worn through.
- New parking brake mechanism as it got sticky when cold.
- New driveshaft seal on the differential due to a small leak.
- Finally the big one, four new camshaft adjusters as there's a part inside which wears over time and they start to rattle. These are quite a common issue and it seems to be more a case of when not if.
All in that's probably £3-4,000 worth of stuff and each time I have had a nice courtesy car with nothing to pay...