Originally Posted by RCZ

You can argue a few points to why, but its always beneficial to be able to adjust balance front and rear. Arguably, you can still do that by just changing the rear, however some people will be left unhappy even if they set the rear to softest. I've always thought balance should be alignment induced and then you can change the tendencies of that setup using adjustable swaybars. Doing swaybars first is backwards.

There arent really negatives to installing sways. Specially milder ones like the Stillen bars. Remember that going extreme in either direction (hard or soft) is not good. You should pick the swaybar by the suspension setup you will be running. If you are running soft street springs, get the not-so-aggressive bars, they will work together. If you are running 8k spring coilovers then get the stiffer bars.

Stiffer isnt automatically better. Better = what works with your car + produces the desired balance.

There shouldn't be any negatives. You might start tripoding around when you go into driveways sideways and you might hear a little more noise, but its nothing to worry about...unless your bar is walking. Thats the thing with adjustable bars, you have to tighten them down like crazy or they will start shifting around under load, causing a very distinct clank. Its very annoying, so I for one, don't have much of a problem with a non-adjustable front on my non-racecar.