Well an 8 lug rim will not work for you, that's for sure.
It really depends how big of a tire you want to run. I'm not familiar with JKs at all. I can tell you from the quick research I did this rim:
(Same rim you linked but in correct bolt pattern) will stick out about 1.75 inches further than the stock 18" rims. Will it fit? It'll bolt on. Depending on tires it may or may not rub. I'm sure someone more familiar with JK's will chime in and help. Aggressive? That's up to you. I like a tire that sticks out a bit. Just the rim sticking out an extra 1.75" and then a tire hanging an inch or two even further out? Sounds a little aggressive to me.
For reference from what I found. The JK is a 5x5 bolt pattern. Your optional Sahara rims should be an 18x7.5 with 6.25" backspacing. If you want to keep it close to stock try and match up these measurments. Maybe look for a 17x8 with 5.5-6" backspacing. Remember the lower the backspacing the further it will stick out. Like I said I know nothing about JK's and this is real general information so take all this with a grain of salt.