wheels

i have been semi restoring my 76 for about 3 years now and im getting close to getting it painted and driveable i bought 15x10 eagle alloys but i think it would look alot better with 18 inch wheels are there any problems with 18s? are either of them better than the other?

4x4alaska has them on his rig;

http://classicbroncos.com/forums/attachment.php?attachmentid=28939

only thing you'll have to address is wheel backspacing, depending on the size you go with. 18's have a lot deeper backspacing on them.