I believe I had the SR-71 kit. It was one of my better models, but it didn't survive the movers when I moved my stuff from Mississippi.
If it is the same, the only problem I found was trying to mate up the fuselage pieces. Everything fit well as far as edges went, but there were seams in the middle of the plane that caused the lines to sag due to the fact that they were self supporting. I glued a "support" in to keep them from pinching in before putting the pieces together. I know that makes little sense, but when you fit the main fuselage together you'll see what I was talking about.
MiniD