Any disadvantages to the adjustable one? I don't mind pay the extra for it but was curious if there might be a reason why I would want to go this route.

 

The adjustable one bolts on then has the capability to spread and put preload on the chassis to keep it taught from flexing inward. Yes it is a good thing. I tack welded my GW unit in place and I have added a few preload braces onto my car that no one else has. It does help keep the chassis stiff laterallty for cornering.

If I had a very detailed camera lens I could show you a picture of the custom brackets on one of my preload braced that is slightly bent from cornering loads. I need to someday double sheer the mount brackets. Its single sheered with 3/16" steel stock, but still very slightly tweeked.

Solid ars are stagnant loaded and flex inward still. Preloaded bars will maintain chassis geometry under load. This is getting on a very upscale measure of performance that will only matter if the rest of the car has a worthy suspension just as solid and will pull substantial g loading.