Welcome to the Forum
The first thing that you need to do is determine how much money you want to spend and go from there. All models can be lifted and modified. I believe that the TJ has the most aftermarket parts available.
If you are doing the work yourself you can save a lot of money. If you are referring to having someone else work on them, then they are all no cheaper or expensive than other vehicles.
Best engine, most prefer the 4.0L, I-6.
What you decide to go with is entirely up to you.
When you find something that you are interested in post it up in the appropriate section (CJ, YJ, TJ, or JK) and we will help you out as much as possible.