Short history; I sold my 2017 911 about one year ago. I loved the car but wanted something easier on my back entering and exiting. Being in my 60's, I was ready for more of a touring convertible. My first choice was an M850. My thought was to get one pre-owned because of the history of high depreciation. Obviously that hasn't happened thus far. I did demo one a couple of times and really liked it. I ended up ordering a 2021 MB C63S convertible that I have owned for 5 months. I was able to get a good deal at 7% off. I like the car but find a few things quirky with jerky starts and steering while taking lazy curves. The steering wheel stays in the turning position and doesn't easily return to center. These charecteristics are well documented in this forum. I have the opportunity to purchase a 2019 M850 convertible with only 1,500 miles at a very fair price. Even better, I am able to drive the car for a couple of weeks before making the decision to purchase it. The MB dealership will give me what I paid for my car and possibly a few thousand more. They will also do the transaction of buying the BMW and selling it to me for a just a transaction fee which will save me having to pay the tax.
My question to forum members is there anyone that has owned or logged miles on an M850 coupe or convertible and could give me a comparison to the C63s convertible. Obviously I am going to be able to compare the two myself but I would like to hear about what others think. Appreciate any input.

 

Forty-two views and nothing....

 

The last thread he started on the very same subject has over 500 views and nothing.

https://mbworld.org/forums/c63-c63s-...-bmw-m850.html

Clearly nobody here who has made that move or compared the two. More of a competitor to the SL, which wasn't exactly flying of the shelves lately. Very different vehicles, and convertibles are such a tiny niche. Especially these compromised coupes with chopped off roofs and a ton of weight added. The M850 weighs over 4700lbs, that's as much as many SUVs. I'd expect it drives smoother given that it has a torque converter automatic and is positioned below the M8, but even the M8 is kinda soft from what I heard. Probably not a bad choice if one wants a fast, but more cushy old age car. I think the crowd here is too young on average.

 

I have had the opportunity to drive both almost side by side. I received the M850 over the weekend so I was able to log some miles both highway and city driving. The M850 is fast and very smooth. The exhaust sound is not impressive or natural. Today I drove it to my dentist appointment which included highway driving. The M850 is very capable but felt like I was driving a big car. When I got home I got in my C63S convertible to do a few errands. I have been very OCD about properly breaking in the motor thus far, which is suppose to be till 1,000 miles. I had 960 staring today so it was time to start having some spirited driving especially so I can get a better comparison to the M850. Immediately I felt a more "feel the road" kind of drive. Definitely not as smooth as the BMW. Coming out of a 911, the C63S felt heavier and not as nimble. I got a whole different perspective today when I got back into the C63S after logging a good amount of driving time with the M850. As crazy as it sounds, Going from the M850 to the C63s today was the same feeling I got when I went from the nimble ride of the 911 to the heavier feel of the C63, only this time my C63 was the nimble feeling car. I put it through the paces and really felt the difference. The C63 was really fun to drive. Yes, the tranny makes start ups a little more jerky but you learn to accelerate in a way that eliminates that. I want to cover a few more aspects in comparing the two cars. Seat comfort and driver position goes to the C63 hands down. The seat position and height of the 850 is not comfortable for me although I did raise the seat almost one inch from the chassis and it made a good difference. This modification to me is a game changer.
The C63 is not touchscreen but navigating through prompts and set-up, especially the radio is more effortless in the C63. I have the standard Burmister stereo and must say, it sounds really good and a HUGH sound upgrade to the standard Harmon Kardon found in the M850. It is very sad that BMW really dropped the ball when they used this stereo in such a high end car. Another Hugh plus for the C63 is the overhead and back up camera. A big improvement over the M850. There is a view of the front low bumper that is accurate to within an inch of the curb with a clear, up close display. I do like the "cockpit" effect better in the M850 but the C63 wins the functionality test IMO. All in all, body styling and refinement goes to the M850. My M850 is Dravit Grey, a color that is not one of my favorites but the M850 still stands out when compared to the C63.
My gut feeling is to stick with my C63. The "fun" factor alone is a game changer. Could be wrong but I was very lucky to be fortunate enough to compare the two side by side.

 

Good comparison and pretty much as I expected it. I hadn't realized that you weren't even through your break-in period, so yeah you really haven't experienced the C63 yet. I'm guessing you've been driving it in C up till now. It'll only get better from here. For me it really woke up around 8-10k miles and it also took me a while to find my Individual mode configuration that hits all my notes. For me that's everything in S+, AMG DYNAMICS in Pro, but suspension in Sport and transmission in M. I use this for my regular highway driving and on open roads, but the car really wakes up in the canyons when I put it in Race mode with transmission in M and ESP in Sport. With shifting your own gears, the transmission does what you want and you can drive it smoother than in automatic mode.