Hi Zaps- Hows it ?? On your NQD you will want a 3650 or 2860 range motor with 2200 to 2700 kv and about a 30mm prop. For some speed use 3 cell lypo battery, 4500 to 5000 mAh Last time I looked HK did not have any marine motors in this kv range. if you get a 4000 kv motor you will probably burn up something. There are pages in this forum that discuss the NQD mods and on other forums as well.
Have fun !!!