I have 29,000 miles on my MP4 but it is also a 2014 which I know had a lot of redesigns like the door closing correctly without slamming over the earlier models which had to be slammed without requiring the soft close option. I know the manufacturers make changes as much as every month and never tell the public or even the owners, sadly.
Yet, I drive my MP4 EVERYDAY and have used the horn a few times, including yesterday in the rain as another auto almost tried to get into my lane without seeing me there (lol, our horns are loud, he corrected himself quickly). Still, my horn has never stuck or gone off at random. actually, other than complaining about the IRIS II which is now WONDERFUL except for FM reception and no HD on FM, Navigation is truly outstanding as is Bluetooth and the Meridian speaker are a joy, - I have not had any problems to speak of on my MP4 other than replacing a fuel sensor and my headlights which suffered from premature condensation.
For whatever it is worth, I have also test drove some earlier MP4s and was surprised how they performed and handled a bit less, I sure would like to know what McLaren did to improve on the 2014 models. I know McLaren planned to continue production on the MP4 along side the 650s so I can only imagine, especially in driving, how much the 2014 model improved (too bad there are sooo few of them in comparison though most all are spiders, oh, and just having the rear window open on the spider making the spider worth it even if you do not put the top down, Truly a Joy in MANY, many ways)), has anyone else experienced different years to speak of the differences? I do not drive on the track so I cannot address that part of it. I was also told the 2014 may have had improved cooling system??? I have taken my MP4 to 201 mph GPS verified and noticed I had a lot of room to go much faster but the speedo was way off which I was told is normal for all autos brought into the USA since there is a Federal law requiring it. cooling system did not move but tires got hotter. I wanted to make sure I could easily go over 200 mph since I have been told many auto claim they can, even other McLarens but they only come close.
Also, for whatever it is worth, I LOVE driving my MP4 in the rain and am soooo impressed at how quickly it stops from 100 mph, I have CC Brakes but I imagine at only 100 mph there is no real difference but it the spoiler popping up sure seems to cause the auto to pull back, this may be my imagination, but I love the whole process either way.. I also still have original wiper blades working perfectly, not like on my Porsche where they have to be replaced every year and still not do as good a job as the one on my MP4.
Oh, can you tell, I LOVE y MP4 and doing my best to hold on to it but I know eventually I will have to sell it, not rich like most of you but really fortunate to have enjoyed it for three years now!!! Thank you LORD...