i can't tell you anything definite, so 'apparently'
there's plenty of early celica's around NZ, although they're not the sort of thing you see on the road every day. i don't know anyone who actually daily drives their one and i know quite a few people who own them.
as for importing there's quite a few early rotaries like r100's and rx3's being imported from Aussie lately so if they can be complied then i don't see why a TA22 can't. our wof's aren't exactly hard to pass, although for any major mods you'll need a certificate of roadworthiness. a bit harder to get but still a lot easier than things in Australia it seems. you do need to get a new WOF every 6 months so you do need to keep your car up to a certain standard but if its something worth importing then that shouldn't be a problem.
hope that helps, if you want to talk to some of the people importing cars then you should try the message board over at rotahavik (http://www.rotahavik.co.nz/phpBB2/index.php, just throw up a question and somebody should be able to help.