Unrefined, maybe. But the turbo JDM versions make bucket loads of power.
I have no experience with the SR20 DET engine but I can say that the KA24 DE was not well suited to use in a sporty car at all. The KA24 was not eager to rev, when it did it didn't sound happy and it ran out of breath well before it got to the redline. It encouraged you to shift up earlier rather than later.
The KA24 would have been a much better match with an automatic transmission.
I was, of course, kidding with my original comment. I'm sure that a modern version of the 240SX would share absolutely nothing with its predecessor aside from occupying a similar market niche and having a FR layout.
^^^^In the last issue of Import Tuner, they put that myth to the test to see if the 240SX is the shizzle or not. With and without turbos. Turned out it's not the handling gem that it has always been bragged about.
I'm not surprised. The 240SX was light, about 2700lbs, but the chassis felt flimsy. My Miata feels more solid. I shudder to think what the 240SX convertibles must've felt like. (They were regular coupes that came off the assembly line in Japan then were shipped to California to have the roof cut off, no extra structural bracing was added at all IIRC.)
AFAIK Nissan's S-platform was fairly old when my 240SX was new some 15 years ago.