For those of you interested. I've been trying to figure out if the if there is any difference in the suspensions between the Base X3M and the Competition model. Luckily fortune smiled on me and I was able to do a pretty thorough comparison.
So two local dealers both got base X3Ms with 21's and X3M Competitions with 21s. I did back-to-back test drives at both dealerships over the past two weeks (taking advantage of the 50 degree plus weather we've had here in NJ so I don't slide around on rock-hard summer tires). Exact same roads/routes on both set of drives, so this was a really good comparison.
There is definitely a difference (not massive, but noticeable) between the suspension setups on the base vs. comp models. While it is certainly possible that the actual suspension components are the same, I wouldn't be surprised if there is a difference in the software tuning of the adaptive shocks between the two cars. Having had the Dinan Shockware software flash on my '17 340i Adaptive Suspension package car proves what a difference a simple software change can make to a BMW Adaptive suspension's feel/performance
I'm comparing "comfort" mode on both vehicles here as that is mode I'd need to be in 80%+ of the time in order to keep some degree of comfort on the crappy NJ roads I drive daily.
On both set of test drives, I noticed that on small, rapid sets of bumps/undulations the Comp car seemed to "crash" over the bumps and really bounced me and the passenger around much more. It felt like the car was riding over the bumps as opposed to absorbing them. It makes for a very jittery and unsettled ride. Frankly, there is no excuse for this kind of behavior out of a BMW as they know how to make a car firm yet compliant. You could actually hear the impacts more in the Comp car as well. Surprisingly, the Comp models "Sport" mode seemed to handle small undulations better. Yes it was firmer, but Sport seemed to take the edges off the impacts slightly better. Weird. Sadly I couldn't stand driving around a Comp model in Sport all day, but maybe those of you with smoother roads could.
I asked my CAs to pay attention to how they felt going over the same set of bumpy roads to help me see if I was being crazy or not. They both agreed unprompted that the base model seemed to handle the bumps better and that they felt the bumps much more in the Comp model. They also said that they felt they were being tossed around more in the Comp. I had a backseat passenger too at one of the dealerships (Genius was really interested in seeing if there was a difference between the two models) and she said that the ride in the 2nd row was much more unpleasant in the Comp model.
One thing I did notice (and which supports the Car and Driver quote about the anti-roll bars being thicker on the Comp models) is that initial turn-in on the Comp felt quicker/more responsive than the base to me. One of my test drives lets me take some really high-speed (like 60+ MPH - might have actually taken one long turn at 90) country back road sweepers and the improved turn-in of the Comp was easily felt. This actually made the steering feel a bit better/more responsive on the Comp as well. I felt more comfortable pushing the Comp through high speed turns as long as the roads were smooth. If there was any roughness/bumps to the turns, the Base model felt noticeably more stable due to the better damping. The Comp got a bit "skittery" on me on one high speed (50+) bumpy turn, which really shook my confidence in the vehicle. Proof that ultra firm is not always the best choice for handling.
I also quickly found out that the "Economy" throttle response mode is crap on either model. Put it in Sport if you want proper throttle response. It completely wakes the car up and almost makes it feel like they put a different engine into the car.
One other item if you care about 2nd row passenger space/legroom. The M Sport seats are definitely thicker than the base Sport seats in the Base model. I intentionally drove a second base model at one dealership just to see if I liked the base seat better than the M Sport (standard in the Comp, upgrade on the Base). After my drives I always get into the back seat to see how much legroom I have. For reference, I'm 6' 1.5" with fairly long legs and drive in a fairly proper "racing" position (seat back fairly upright, legs relatively straight, wrists rest on the top of the steering wheel while keeping my back against the seatback). With the base seats, I still had about 1.5" of clearance before my knees hit the back of the front seat. With the M Sport seats, my knees were just touching the back of the front seat. While it is possible that I was in slightly difference driving positions as the seats are different, bottom line is that it looks the base seats in the Base model will net about 1-1.5" of additional legroom. They are also softer cushioned and the seat bottom is wider (if you've got a big ass - stick with the base on a Base model).
If I could get the ventilation, I'd probably stick with the base seat on a Base X3M just for the additional 2nd row legroom, but I really liked the support/feel of the M Sport seat. Plus the leather is nicer and you can get the ventilation option, which I love. Maybe I can find a way to change the driving position a bit to get a bit more legroom for the rugrats in the back.
So right now, I'm leaning towards a base X3M with the upgraded M Sport seats. I'm curious if BMW will address the ride quality criticisms with the 2021 model. If they improved the "Comfort" suspension setting on the Comp, I'd definitely go that route.
I'll definitely miss the better exhaust note of the Comp (yes, it is noticeably meaner/louder) but the power difference is negligible and can easily be solved with a tune. Ditto for the exhaust and black grilles and such - easily fixed problems, though they basically eliminate the cost savings of getting a Base model.
Overall, I felt really comfortable driving the X3M and am astounded with how much raw performance is available in an SUV. This really does feel like a jacked-up M3. Yes, you do still feel the weight and high center of gravity when pushing the car (compared to a coupe/sedan), but only folks with a lot of driving experience will really notice. I'd love to drive an M Drivers' package car to see if the weight loss of the sunroof would make the car feel even better. It certainly couldn't hurt, but not sure if I would really notice it shy of a racetrack setting when really pushing the car.
If you've gotten this far, thanks for reading my novel. . .