Ok, as a closure to this question I would like to post my findings for anyone who finds it in the future.
If the rim's centrebore size is smaller than the car's centrebore cone size, then it will not fit because this is like trying to poke a big stick into a small hole. This can be rectified by making the hole in the rim bigger.*
If it's a small stick into a big hole, it should be easy to get some adapter rings to fit into the rim's hole so that the hole exactly matches the car's centrebore. This is important because the purpose of the centrebore bit is to make sure the wheels are installed perfectly centred. My research on forums is that if you don't have the rings installed, the wheel will possibly be slightly off and there will be vibration at certain speeds which wheel balancing cannot cure.
* I found on lowyat.net some threads mentioning rim repair etc, so I called up one of them (Wan Sing Sportrims Services) to ask if they can make the bore bigger. Can, but depends on the rim (if there's not enough metal to cut, it will damage the rim). However, I did not have the rims yet for them to look (i was only
considering getting Honda Civic FD2 rims for my Inspira). So I looked online for photographs of that rim model (back view to see the mounting face of the rim) and brought the photo to Wan Sing to get the technician's opinion. He looked at the rim, and said there's enough material to cut (I only needed to increase the hole diameter from 64mm to 67mm, so it was just shaving off 1.5mm of metal inside the wheel). Cost he didn't dare to commit- he's not the boss. But he said less than 100 for a set of 4 rims to increase bore size.
What they do is to clamp the rim on a large turning lathe and just cut the hole bigger. I saw him cleaning up a huge rim (looks like the big ones that someone might put on a Porsche Cayenne) by cutting away a thin layer of metal to expose a new shiny surface.
The sohp itself looks legit, there are PILES of huge ass rims being refurbished etc. Plenty of machines in there too, mostly lathes and similar turning equipment.
So now i'm actively looking for a set of Civic FD2 17" rims (the 7x2 spokes kind) for my Inspira. Anyone got a good rim+tyre deal can hit me up with a PM