I have a heim joints on all my arms, 110,000 radial load capacity- I believe currie or JJ even make ones that are like 215,000 radial load. I would be more worried about the axle bracket or frame side bracket breaking before a heim joint. Hence the reason I reinforced them both, I wheel pretty hard and have had track bar brackets bend and all sorts of axle carnage but never with the upper arm joints or brackets (knock on wood) like I said if properly designed and built 3-link is the route I feel is best for most types of wheeling. But hey man its your rig if you want the added strength and peace of mind with a 4-link then do it

 

Coil spacers are cheap and easy to install, but they generally give you less flex because if you had a stock coil laying next to say a 4" lift coil, which one will be longer? The longer The coil, the more flex you can have before your coil pops out. Spacers lift you without helping down travel like an actual coil would do. My front RK coils are 28" with no weight on them,stock zj fronts are about 15" I believe- that gives me roughly 13" of additional down travel before a coil pops out. Sadly I still have to have limiting straps because I still unseat coils

 

I am running a well used set of Rusty's 808 springs (6.5). I have no issues clearing 36" TSL's with moderate trim. As for the one bolt.. they are 5/8 bolts.. If you sheer one of them.. you have other issues

 

I have the rock kralwer 3 link too. Solid and very well built. Rides great! As for flex its maxed out my shocks for my RC 6.5 inch coils so I can't tell how far this thing will go.

 

3-links are awesome! I had a y-link for a long time before upgrading and I love the flex of the 3-link.