Yes it is possible to put a northstar engine in the DMC. But with any engine swap there are a few things to consider. One is the mounts, which need to be moved slightly in order to fit the larger engine. Also, is the location of accessories like the alternator ect. I've seen such a setup and it works great when all the details are gone over. Much better than that other junk original six in there.
www.delorean.co.uk has an article on the PRV V6, and has ways to get serious power (250+ HP) from the PRV V6.
The best conversion I have seen use a longitudinal twin turbo Mazda triple rotor rotary engine with a porsche 911 gear box. Do a search on Google if you don't believe me. 0-60 4.5 seconds and 165mph top speed. Looks lovely in black much better than the silly brushed stainless finish.
I believe you. I saw the video snippet of this car in action a few years ago and it simply took off like a scalded cat. The 20B turbo rotary sounds more like a turbine when it's in the higher rpm ranges and has none of the low-end torque limitations seen in the normally-aspirated 12A and 13B twin-rotor engines.
This car was, at that time, registered in Florida and was advertised for sale for around $25,000 or $35,000. I forget which.
I put a flux capacitor in my Delorean and now it drives like a dream! But seriously, this car is great if you have the patience to take care of it. The battery tends to get drained though, so it should be "exercised" once a week or so. I'm fond of the brushed metal look myself.