From the pictures what you have looks like it is the correct y-pipe...
I have used a full NRP kit on my '97 D90 and my first NAS D110, and loved them.
On my current NAS D110 I ordered just the y-pipe from DAP. I like the DAP well enough, but at the time my D110 needed a new y-pipe I bought the cheaper DAP thinking that I would eventuality do the 300 Tdi swap.
Click here for the DAP-> DAP Y-Pipe
Dollar for dollar the DAP option is the better.