I would call rock krawler and see what exactly needed for what you want to do. I'm running a 3.5 inch lift with 37s and never replaced all of that. My jk drives perfect takes turns at 80 no problems and wheels great no rubbing but I did replace my fenders. Call rk there great this is my second jk done with there parts and I am extremely happy good luck with your build!

 

I am very happy with my set up. I have a 3" BDS coil/shocks and 3/4" BB spacers. I am running a 285/75/17 (34") tire. It doesn't look too high or low and the tires don't look "stuffed" under the Jeep. The only reason I went with the additional 3/4" spacer was that I thought there would be rake with the Warn Elite bumper and winch. There wasn't in fact it was higher than the rear so I added rear spacers to even it out for a 3 3/4" total lift.
I have an almost factory ride just a little firmer, it handles great, steers straight and tracks right. You have to expect a firmer ride to reduce body roll.
The items I added after the lift: front adjustable track bar, rear adjustable swaybar links, and front driveshaft.
Also, my tires are no where near rubbing anywhere and they are still just inside the flares (the thread is flush with the flare and the sidewall sticks out just a bit).
I have 17x9 wheels with 0 offset so I believe that is a 5" back spacing and stock is 6.25", the only thing I would change would be a little bit of an offset to get the tires a little further under the Jeep so I don't have any problem with police or inspection).

 

Like some ppl have stated already if your looking to do 4" go for it. It's expensive but doesn't have to be all at once especially if your not crazy into wheeling. Buy a rather basic kit and make sure it has 70% of your items listed and build on it from there. Buying things later will cost more rather then getting a complete kit but I think many of us can say we're not rich. Good luck.