I don't know about the Highlifter arms, but I can tell you that with the SATV arms the Prolift won't fit becasue the SATV arms are built with heavier material and slightly different architecture that OEM arms. The SATV arms come as a pair for each side, upper and lower arms are included. As gmck states, they move the front wheels forward about 1.5". If the Highlifter arms move the wheels forward they would need to come as a pair as well, otherwise caster would be affected and ball joints would be likely to bind.
One advantage to the SATV arms, and the reason I chose them, is adjustable camber. I was wearing stock tires badly with the stock arms. I don't believe the Highlifter arms have adjustable camber if that is important to you.
The lifts and the arms will come with steering stops. If you install them as per instructions your turning radius will be noticeably increased. Information varies, but without the stops the CV joints in the axles can bind due to increased angle at full suspension extension and turn to lock, and break an axle. Another poster on the Forum recently stated he wasn't running the stops and has no binding issues. Your mileage may vary.
