Whoopsy:

Well, one of our fellow 918 owners updated his car and did some runs at Road America. He hit 181mph at the end of the front straight before going into turn 1. 

I have never driven or even been on that track, so I have no reference. Maybe some experienced fellows can chime in. 

All I know is the front straight is around 3/4 mile in length and turn 14 heading into the straight is a 200' radius turn, turn 1 that follows is a 348' radius turn. Maybe some geeks here can whip out a calculator and do some math :)

I did some internet surfing to see if I could find out any comparables (I know - I have no life).  I found this track analysis on the link below.  It has speed trap information for various classes of race cars - they were trapping at between 160mph for GTD class to 175mph for the prototype class.

http://nasportscar.com/bens-analysis-road-america/