Swapped mine last Xmas on a 2000 1.4 Si - I studied the thing for ages before deciding that the easiest thing to do was saw off the old one - did it in chunks to make sure I didn't bugger up anything important inside. Even having the chopped up plastic in my hand afterwards didn't reveal any easier ways that i'd missed - phew.
Ended up being really straightforward, and now have a lovely ally gearknob on (freezing cold on winter mornings though!)
Word of warning - if you saw off the Reno gearknob, the plastic powder is a nightmare, it gets everywhere, and gets engrained into the carpet - save yourself a MONSTER hoovering job and tape some paper or plastic around the area before you start sawing!