am 6' and 32" inseam. (long legs), 160 lb. the 1st xf i tried was a 2004 coupe (base). didnt notice the knee bolster, but fitted well. perhaps because i was in awe i didnt notice if my knees touched.
then drove another. it was a 2005 coupe (ltd) and as still was up on a cloud. didnt notice anything else. even when i drove it back home. but after a month i began to realize that from my knees and the rest below were all full of crusts, so removed the bolster. even so, still was hurting my legs, so i ended up gluing foam all around the surfaces where my legs and elbow touch. black foam; looks nice. still about 1 inch room. no more. and the seat as low as it can be, back touching. my feet just push the pedals enough to touch the floor..
wonder if the 2004 has a knee bolster. i didnt notice it. i was up on a cloud when i drove it. also have noticed that in some models the bolster is thinner. i drive with my arms extended, the wheel almost beyond reach (and have long arms too), and the wheel being without adjust for the angle, is a serious limitation. my head almost touches the ceiling. i have learned to fit by getting my rear 1st and sit, then turn around and fold my legs and squeeze them in. i guess all sports cars are about the same.
i dont think any 1 taller would fit.
and i think mercedes designed this car for europeans, that are not as tall as north americans.

still, wouldnt change my car for anything else. when i drive it am in another dimension.