I had an N4 in my sights at a local dealer's closeout sale last year. I could have got it for about US $300-350.
It was really well made, but in the end I decided against it as it wasn't really my bag, and who knows if the things will ever attain any real kind of vintage status. It had a swamp ash body and maple fingerboard, and sounded very bright. In the end I grabbed a fenandes sustainer guitar.
I went through a bit of a Nuno phase. I remember working out stuff like 'pornograffitti' and 'get the funk out' note for note. For a while, the string skipping/tapping part from 'he-man woman hater' was one of my guitar store party pieces.
Most of Extreme's stuff sounds a bit cringe-worthy nowadays, but check out their last record, 'waiting for the punchline'. It bombed at the time, but it's a very cool record, and the only one they did with decent production.
The cool thing about Nuno's playing is that he had a great sense of rythm and how to play in or against the pocket. Quite honestly, their attempts to work funk into their music were often hilariously cheesy, but Nuno definitely knew how to make his lines rythmically interesting and alive, which is something so many rock players from the 80s missed completely.