I believe in EcoPro mode it lives in top, but in full fat Sport mode it won't go above 7th unless you shift it up manually.
I haven't driven it enough to have an opinion about it being sluggish, but it picks up a damn sight quicker than the Barge... Twin turbos help and the straight six is a torquey lump 
The bmw will default back to comfort mode at each start up, you'd have to physically select EcoPro (which makes it as flat as a witches tit as it encourages you to ease off to maintain speed). Of all of the 335's/435's that I've had, they've all been like a bullet. Fantastic around town at low speed and instant pick up when you floor it. As to sport mode, I'd use it to stretch the rev range lower down but switch it off when I was on full chat. My Audi is the same, no need to be in sport mode when flat out, as you can achieve maximum speed in 'D' ....... allegedly.

The 35d's are a cracking engine mated to a cracking gearbox so certainly shouldn't feel lazy.

Mine have all pulled like a train straight off the line, with a very slight lull around 124-128, and then off they go again with the same urgency all the way to the limiter (on a track obviously). Fuel wise I'd get mid 30's around town and 48-50mpg on a run. I really do love the versatility of that engine and gearbox set-up.
