can i drive highway speeds with the high steer? or do i have to do something else?

 

yes if you installed it correctly and your tires, bushings etc etc are all in good shape

 

I SAS'd my rig which is my daily driver and it runs just fine on the highway. Hell, I don't even have a steering stabilizer and I can drive 80 down the highway with just a finger to hold her in a straight line.. Shouldn't have a problem