The cable described in box #1 for $90 is the correct cable I need to link my desktop to my car (in sig), right?

THE CABLE

Also, would y'all go with the USB style cable or the RS232 type cable?

 

Right you want the cable at the top of the chart. It will work great. The only reason Id ever get a USB cable is if your lappy doesnt have a serial port. USBs can't be locked in place like a serial so you risk pulling the cable out while you log data(not a big deal) or when you flash the PCM(kills the PCM).

 

www.obd2allinone.com .might find some usefull stuff here too