Hi Lushpuppy,
I did google as well and found a DIY fix on the Sat Nav touch screen.
I contacted Lexus of Chatswood and they asked me to bring it in for them to take a look at it.
Unfortunately, my car is already out of warranty. So definitely, they won't replace the whole unit for free and probably end up costing to fix it.
I will bring the car to the dealer and see what they have to say. If it is costing over $2K, I will probably try to DIY the touch screen myself.
Thanks for your feedback,
Brandon