Hello everybody.
So my XJ has 166k miles and the previous owner had it seating outside for about 2 years. Every time I drive it I feel like there is something wrong with the suspension, It takes bumps really hard, and when I'm driving down the street it wobbles like crazy. which major parts should I replace, is it a DIY job?

 

From your description that's classic symptoms of bad shocks.

What I would do is use google/forum search and find the best write-ups you can on checking each suspension component, including:
shocks
springs
ball joints
sway bar links
track bar
tie rods and steering components

I would as part of this take a close look at all the bushings for dry/cracking and looseness - stuff like sway-bar to frame, control arms, leaf springs, shocks.

I would replace anything that's questionable.

Most everything is a pretty straightforward DIY job. Some stuff may require specialty tools that you can rent for free from your local parts store.