I installed my new DRD on my 07 WR450 and it took about 15 minutes total.
I spent another 15 minutes trying to line up the header so that it cleared the top bolt on the oil filter and it DOES NOT. Not matter how I fussed with it...when it's torques to spec it will not clear the bolt.
Since mine is the complete system I was curious about weight vs. the stock system. The DRD weighs 6.54lbs. complete. The stock unit weighs 3lbs. more. The DRD is 3 inches shorter at the back of the bike vs. the stock system. My unit shipped without the quiet insert...it sounds awsome and I probably will not run the quiet insert when it arrives (I purchased it with the system...it just didn't ship with the system).
I'll post up some pics tomorrow.
Ha! See I'm not crazy!