For those of you building B&M coasters, and those who will call a B&M design "unrealistic" because of fast pacing, keep in mind that some of the first B&M coasters had amazing pacing. They got slower with age.
http://www.youtube.com/watch?v=ErMyGSw819I
http://www.youtube.com/watch?v=Qrs2KYEwxaM
http://www.youtube.com/watch?v=oB9xE5aTw7M