Hey guys, I drive a 2006 Civic Si coupe, supercharged Stage 2. I'm not here to spam, berate or mock anyone, I'm here just to post comments, facts and info. I come in peace =)
No more guessings for you question. I can personally tell you that the 535d is faster than the 335i coupe stockwise. Its only a bit faster, towards mid and top end speed, I can tell you the difference is not too big. Because I have personally raced with both vehicles with my Civic Si on the same highway with my same mods to a speed of 145mph where the 535d is at my rear quarter panel and 335 at about 2 car spaces behind the 535d.
The difference is less than half a second from 0-60mph. But if you talking about longer range/higher speed, the 535d will starts to overtake the 335 at about 100mph. This is stock vs stock.
BUT there is one fact to know is, 335 has more potential than the 535d, one simply stage 1 upgrade kit can boost the 335 to 380+hp so its more fun and more options to play around with.