150+ MPH on an interstate? Seems ill advised at best.
One of my engineer friends that designs transportation corridors once mentioned that roads, whether local or interstate, are designed for a particular speed + a safety margin. That includes things like guard rails, turn radius, crown of road, shoulders, etc - beyond the safety margin, things can get pretty unpredictable and lead to some pretty serious consequences.
2am = reduced visibility. I don't know about Oregon's wildlife, but I've passed many moose, bear and deer late at night on highways up here. I've also seen the results of a deer jumping into the path of an oncoming vehicle and a moose going through the windshield of a 911 - not something you would want to take your chances with.
Personally, I've gone off a race track at speed a couple of times - I can't think of anywhere on a public highway system that I would want to do that. Got an itching for speed? Why not take it to the track. Top speed in a straight line? Who cares - there is always someone that is faster than you. In this case.... a bone stock 1984 928 S4 or is that too exotic?!
Basically, I'm suprised an ex-cop would behave this way- If he had any highway patrol experience, he's probably had to clean up some accidents in his time. Why chance it?