[19x]

Originally Posted by NathObeaN

I think it's the cumulative affect. Yes, I wouldn't be able to tell the difference in weight purely when comparing seats, but a kg here and a kg there and it all adds up so if I can save on unnecessary weight (and it costs less), why not? For me however the biggest concern was height difference (I'm a tall guy). Appreciate the feedback though and certainly don't disagree with your point.

The cost saving and height concern make sense. For that, I just opted for a slicktop (no sunroof) in my prior M3's. In my experience, the most headroom can be gained by eliminating the sunroof. An extra 2 inches or so. Especially useful when I tracked and autocrossed with a helmet (for reference, I'm 6"1' or 185 cm). That extra few inches made a world of difference.

When it comes to weigh savings, the most important thing to consider is not how much weight is coming off, but where the weight is coming off from. If I had to choose between -50 lbs for no sunroof vs -100 lbs for lightened seats, I would choose no sunroof every time.

[chris719]

I've not found any evidence that the manual seats sit lower. Would be happy to be corrected, though.

[Moflow]

Originally Posted by 19x

The cost saving and height concern make sense. For that, I just opted for a slicktop (no sunroof) in my prior M3's. In my experience, the most headroom can be gained by eliminating the sunroof. An extra 2 inches or so. Especially useful when I tracked and autocrossed with a helmet (for reference, I'm 6"1' or 185 cm). That extra few inches made a world of difference.

When it comes to weigh savings, the most important thing to consider is not how much weight is coming off, but where the weight is coming off from. If I had to choose between -50 lbs for no sunroof vs -100 lbs for lightened seats, I would choose no sunroof every time.

Even though I have a sunroof, I’m inclined to agree. You have to remove a lot of weight before it becomes obvious imho. WHERE the weight is located is much more important, whether you’re lowering the center of gravity, changing the weight distribution or even just shifting the polar moment of inertia. Those things all need a lot less of a change to be felt.

[19x]

Originally Posted by chris719

I've not found any evidence that the manual seats sit lower. Would be happy to be corrected, though.

I don't know about M2's, but in older generation M3's, the manual seats were definitely lower (at their lowest setting) than power seats. My friend owned an 02 M3 with manual seats and those were over an inch lower than my power seats in 04 M3.

[chris719]

Originally Posted by 19x

I don't know about M2's, but in older generation M3's, the manual seats were definitely lower (at their lowest setting) than power seats. My friend owned an 02 M3 with manual seats and those were over an inch lower than my power seats in 04 M3.

Agreed, but I mean on the F8x platform. I haven't come across any measurements, just anecdotes.

[gmhl10]

I used to have an E46 M3. The car originally came with the power seats. It was nearly 80 lbs per seat. I swapped them out for Recaro Pole Positions, aluminum brackets, steel mounting base which weighed about 25 lbs per seat. Definitely, considerable weight savings to be had there. I couldn't tell you if they made a difference though since I never autocrossed that car prior to the seats, only after. Not to mention, I had other modifications on it that reduced/added weight.

Not sure how heavy the M2 seats are, but I'm sure they're lighter than the E46 M3 seats since they had that stupid air bladder thing in them.

[Poochie]

Originally Posted by gmhl10

I used to have an E46 M3. The car originally came with the power seats. It was nearly 80 lbs per seat

What I've learned, at least with Audi and more likely with BMW also is; US-spec seats are slightly heavier than their Euro-spec counterpart because one, the available manual control option and two, the US has a mandatory requirement for side-impact airbags, to every front seat, which is not required, in the rest of the world..

So, FWIW, you're looking at a 10lbs difference between a typical North American bound seat and the ROW, since most manufacturers take advantage at the opportunity to save a back and lighten the weight, hence, they don't bother adding side impact air bags, on a model, case by case basis.

[AUSf22]

Originally Posted by Poochie

What I've learned, at least with Audi and more likely with BMW also is; US-spec seats are slightly heavier than their Euro-spec counterpart because one, the available manual control option and two, the US has a mandatory requirement for side-impact airbags, to every front seat, which is not required, in the rest of the world..

So, FWIW, you're looking at a 10lbs difference between a typical North American bound seat and the ROW, since most manufacturers take advantage at the opportunity to save a back and lighten the weight, hence, they don't bother adding side impact air bags, on a model, case by case basis.

No wonder the US M4 GTS did not get the bucket style seats!

[prompt]

I have manual seat on my M2C
I can take some measurement if we want to compare seat position