Firstly I would consider why I was going to do it, if it was beacause you just want to do something DIFFERENT!!!!!... then yea give it a go. If it was because the NT-16 wasnt quite fast enough for ya, then put in a OS CVRX .18, great power and the BEST in reliability and a simple drop right in, while keeping your drivetrain relatively intact.
As for the environment...its simply a massive engine and no matter what you run it in its still gonna spew out more **** than the engine it replaced...cmon does a V8 spew out less **** than a 1800 cc 4 pot, just because you shoe-horned it into your Mazda Miata???

Would be an interesting project tho...but do it because you want to sink your teeth into something big...not just to get more power... there are way easier ways...and way cheaper...