A friend had this "professionally done" for is old civic. He ended up going aroound a corner aggressively and the rim cracked at the welds and he lost a wheel and left the road. I don't think the job was really done that well, though. So long as the lug holes are welded VERY well, you might get away with it. I personally wouldn't put my car on wheels modified in that way.
BBS makes nice 4X100 wheels, my favorites are RG-F's
Correct me if I am wrong, but don't civic 4-lugs fit?