Nictrix said:
A quick look at what PBondar posted shows that the final drive ratio is also different between the 18i, 20i and the 28i.
It is also different between the 35i and the 35is so that's another difference between them and not just a map.
That's because that chart compares cars with different transmissions.
The quoted figures there are for a 35i manual and a 35is DCT. The 35i DCT will have the same gear and final drive ratio.
Not sure on the reason for the discrepancy in the smaller engine models, possibly a similar story with the 18 and 20 models having the manual stats and the 28 having the slushbox stats.