no, won't be safe. there's no way you'll be able to secure the wheels in place properly.
over on a GTV specific forum there seem to be a few with wobblies on their V6s withjout any probs, but I'd like to not use them, but there just really aren't many 5x98s around. (can't afford Ultraleggeras!)
i think it should be fine. to be sensible about it, you probably want to check the wheel bolts periodically to ensure they're torqued tightly to the right spec (eg: 80~90 ft-pounds). maybe for the first couple weeks, check things twice a week, then thereafter, every month, and if there's no issues, less-so thereafter.
make sure you have the right hub rings if they are required. that is, ensure the centre bore diameter (the big central hole) is 58.1mm, so that it fits snuggly over the hub. this is very important, because this interface is where most of the weight of the car will be held. when you have wobblies fitted, you will depend upon the hub even more. so if the wheel has a bore that is big, like 68mm, you'll need the right hub ring that pushes into this hole, to reduce the diameter to 58(.1).
'do it right' and it should be no problem in the long run.