Mostly OOB----I replaced the kit tank lines with piano wire. The kit lines were like soft solder---all wonky and bent. The interior of the canopy is scratchbuilt as Special Hobby chose not to do anything with it. I also added a lot of missing detail to the cockpit and ejection seat.
I was lucky enough to spend a couple hours with the X15 at Air Force Museum in Dayton, and the first thing that struck me when I first looked at it was that she is anything but Black. I also worked with Inconel-X where I work and had the perfect color palette to what happens when it's exposed to high heat.
It's very similiar to "gun-bluing" slanting toward black and even silvers slightly at any stress/attachment point.
I was determined that I wasn't going to make a black X15 as is so common.
If you're wondering---I didn't weather the drop tanks on purpose. These were basically disposable or reusable after they were ejected, and were rehabbed and always a fresh coat of paint ---or no paint at all. So typically they always looked clean.
I've got some build pics around somewhere----I'll dig them up and get them posted.