Hi Guys,
I would like to chime in on this issue...
My touchscreen recently also died and reading all the tutorials online about replacing the "ribbon" etc I was a bit skeptical.
I took it to a place in Melbourne, Brunswick specializing in car audio and nav, they replaced the entire touchscreen for $400, Lexus OEM product from Japan. (so I feel sorry for the above guy who paid $750 to Lexus). They also advised me that replacing the "ribbon" would not be a long term fix.
If you guys need any details about the place I got my screen done, feel free to PM me.
Hope this helps anyone,
Jay