I just re-read the original post, and the direct answer: Yes, your existing tires should fit on the Enkei rims. The rims should be marked somewhere with the size, but the 215/70 tires should be acceptable to mount on a 5.5 to 7.0 inch wide rim.
Fun note: Enkei makes a majority of the OEM alloy wheels for Japanese cars and motorcycles, as well many aftermarket auto rims.
http://www.enkei.com/