Not being new to motor swaps and putting a 4g63T into a '97 accent is two different things. Everything and I mean EVERYTHING will have to be custom fabricated to make this happen. If you are looking for a 4g63t swap and you want a hyundai, I would suggest an older model Hyundai since they used to use Mitsubishi motors in most '95 and older models. If you want to use your '97 accent, then I suggest dropping a Beta from a 4cyl Tiburon/Elantra 1996 or newer then turboing it.
That being said, it can be done but never has in an X3 accent that I know of. However, it has been done in an LC Accent by Rigoli (sp) in Australia. This is a professional race shop with all the tools and resources to do the job and it took them several months to build their car. Doing this swap in your X3 should be similar.
There is a replacement for displacement. It is on 2 wheels and 600cc.