Apple CarPlay installation, with GPS - 1999 LS400
 

I am looking to install aftermarket Apple CarPlay for 1999 LS400 which came with the factory GPS/climate control/audio setup. I was able to see on internet that some aftermarket CarPlays would work for install if it does NOT come with GPS. I wanted to see if anyone could give me pointers on: would it work with original GPS setup? And if so, how difficult/easy is it? I’m hoping we are able to give the audio upgrade for this 20+ years old but super reliable car. Thank you in advance!