02 Es300 Nav Installation And Engine Swithch Question

[Pukka]

Hi I own a 02 Es300 and I was wondering if it was possible for me to install a lexus navigation into my car even though it didn't come with it. How much would it cost and where can I get the parts and installation done?

also, is it possible to replace my engine with another lexus engine? I've heard that it wasn't worth the money but I was just wondering if it was possible to replace it with a 350 engine or something similar

Thank you