I have a 2002 GS300 with no Navigation sytem I am getting a Navigation from another GS would it work and does it worth it

 

Its a lot more than just swapping in the NAV unit.. there is wiring, amp, dvd NAV ECU... its more cost effective to buy an aftermarket nav...

 

yes it is possible and a very nice upgrade to retrofit the factory nav in an 2002 gs. yes it is cheaper to install an aftermarket system just speaking of the actual costs of the 2 systems. when is the last time you saw a aftermarket system on a lexus dealers used car lot? the effect on the increased resale value more than offsets the difference in price of the factory nav vs the aftermarket.