David the ST4 is a stand alone unit so you dont need to plug into your Laptop . These auto-guiders have been used for many years with great success rate David.
The price that he is asking is the going rate so I dont think there is a problem there.
Also the pluss for a stand alone unit Houghy is that when your camera is downloading image's your guider keeps on guiding ! very good when you only have a so-so mount .
Louie
