My zj has a 4 inch lift with 31s I was looking at the setup and it still has the stock control arms am I going to run into problems with them. Shouldn't they be longer with a bigger lift

 

i've been told anything over 3" you probably should go longer.

 

I do not think you will run into much issue, with the stock arms you will have a very rough ride and bad handling, I would recommend longer fixed arms, or adjustable arms, or if you have the money a long arm upgrade kit would be your best investment as far as handling and daily driving goes performance, and offroad performance, the stock arms will have horrible flex because they are at such a steep angle the suspension will not compress as easily.