I did the same thing too. I got a set of 16x8 JK wheels for my TJ but desided not to do it after all. The spacers are $200 the tires are $1,200 and you need to modify your TJ tire carrier to hold the JK wheels. In all I found out it will cost me about $2,500. For that price I'll buy new wheels and tires for my TJ and a few other toys.
Also if any one wants them I now have 5 stock JK wheels for sale.