Depends on what you want. The N802 is a little more relaxed/laid back type of sound compared to the 803D. The 803D has a more forward type of sound in comparison. The 803D has stronger bass output and a bit snappier/faster. The 803D also has a more sharply defined leading edge due to the diamond tweeter. This also brings the musical presentation a few rows closer to the listener, more forward type of sound. These are the virtues of the 803D. The N802, due to the separate Marlan midrange design, the presentation is more floating, more 3D type of soundstage. There is more front to back spacing, more layered where the individual instrument notes or vocals have their own defined space. This to me sounds a little more natural and smoother, but with adequate detail, not as razor sharp as the 803D, but I don't think it's that far off if you mate the N802 with the right cables and gear.
So if you value strong, fast, defined bass and want razor like defined images (but in a more 2D fashion), and want a closer perspective to the presentation (more forward), then I think the 803D would fit your needs better. But if you value liquid smooth detail, with 3D soundstage, natural laid back presentation, and that effortless disappearing type of feel, the older N802 will be a better choice.
Good luck !