I have one of D90 tops also and I had a few issues with the top fitting, but Andy over at d90 tops took care of it and made things right. if you have any question please don't hesitate to ask.
When the F*%# did we get Ice cream!!!
"They are, in factory original condition, noisy, they leak water in from the top and oil out from underneath, you can never demist the windows in winter, they handle like scaffolding towers, and use more fuel than Beijing." Richard Hammond