Updating Navi cheaply

Hello, from England I got a SC430 RHD as successor for my 320 CLK – of course with all documents, full service booklet and technically brilliant. For GB by no means the rule … In short, I am thrilled how gorgeous and uncomplicated the SC runs, despite 140′ ml (approx. 225′ km) almost like a new vehicle. Admittedly, not everything is as perfect in detail as with the German Premiums BMW, Benz or Audi, but that was clear to me from the beginning, and I like to take that cheaply nd in purchase. Even the form I like now …. What bothers me are e.g. details of the “on-board computer”, which simply offers little, and especially the Navi, as of 2002/2003! How can you get an update for “small money” (current CD)? Sure at Lexus directly or the online Lexus shop, but if I think about the Benz or BMW prices, I can imagine the Lexus price well. Would I be very pleased about tips! Greeting to all SCler Avon35