I just purchased the LM6508 on ebay. For computer use, it really wouldn't work, because it's not vga, also the touch screen is specific to the software that the unit uses, it's not a touchscreen you could use with your computer. The picture quality isn't that great. With the contrast and brightness all the way down, it's still too bright and harsh. The main reason I bought it was for radio use, and a cleaner looking install. I have the video out to my xenarc screen, and the picture quality is pretty good. Only problem I have is an extremely high pitched whine coming from the unit itself. Sometimes it goes away after about 20 minutes. I'm not sure how to fix that problem.
And the rader input is a "backing radar". I think it's one of those devices that let you now how close an object is behind you.