Congratulations! You have just joined the ranks to which very few worldwide can say they belong... you're and NSX owner.
I too recently made the plunge back in March and I love mine. If you love your 91 automatic, just don't drive the 2000 6-speed, you will drool for one of them. Glad you like yours. Blk/Blk is a great color for 91. Looks like you are driving the Batmobile.
Enjoy and drive safe. Also check out the FAQ section for other great repairs awaiting you as an owner of a high mileage 91. Don't wait till it breaks before you fix it... it only costs more.
Gordon G. Miller, III
Y2K NSX #51 Yellow/Black