They also say that Honda would replace the H22A4 block with this one while under warranty.

But as far as im aware curtis is correct there exactly the same there maybe 4kw extra but unsure. Im pretty sure Atts Preludes which were produced after 1998 got the H22z1, leather seats, red top and honeycomb grill.

Give these a read:
http://www.preludeaustralia.com/foru...highlight=h22z
http://www.preludeaustralia.com/foru...ighlight=h22z1

Jump on PA (Prelude Australia) and ask, someone will help you out there