the 405 freeway

As long as nobody else is put at risk I'm not going to judge - I mean seriously, the amount of power and technology in these cars nowadays is amazing so how can you resist pushing it occasionally and I'd always recommend a closed track over a public road - that's an M series BMW so I'm assuming it was secure and stable at speed.  I have an F150 with a 411 HP 6.2 L and there is no way I'd ever push it to even close to the limit of that engine because its a pickup truck not a finely tuned sports car.  That and I'm a conservative old fart 

and I'm pretty sure it would fly apart

Having worked in a hospital as a kid in housekeeping, one of my duties was to clean the autopsy room. Many a person ended up there due to their "need for speed". I admit that as a youngster, I succumbed to this dangerous habit, but in retrospect realize that but for the Grace of God, none of my co-workers had to clean up what was left of me. An accident (an unforeseen occurrence that happens without notice) at these speeds leave little, if any, evidence that you were at one time in one piece. The price for a short thrill or a bragging scenario, to me, isn't worth the risk. You may be different, and if you are, I hope that nothing ever happens to you. Aren't there enough things in the current world that can, and will kill you, enough of a challenge in daily life. Why tempt fate.....???
My opinion and am not chastising the OP, but wanted to voice it.

Knothead I'm with you on this - I get it, we were all young once and some of us still are and sure, if you want to take risks that you think don't directly harm/involve anyone else then fine, but you bring up another perspective that most don't consider - do your actions really not effect anyone else?  Not just loved ones left behind but first responders and everyone else in the chain that cleans up the mess.  First responders have a very high rate of depression and suicide as a result of many factors but the carnage they deal with all too frequently plays a large part.  Some 30 years ago when my sister was a radiology resident she was tasked with imaging the remains of a young police officer who was struck at high speed by a fleeing suspect while laying out a spike belt.  I know that had a profound effect on her.  The young man's family, his partner who was standing not 10 ' from him at the time and the first responders all traumatized.  I don't believe the guy driving the car intended to kill that police officer but poor judgment and speed resulted in tragedy.  And it often does in one way or another.

So my advice is to keep your speed trials on a closed racetrack.  Bad things can still happen but you can minimize the unintended consequences.  And make sure you carry plenty of life insurance for your loved ones.  Check the fine print too, you don't want exclusions for racing.