Looking at a 2003 rx 300 has 180,000 miles how many manys do you think I can get out of it?

with the car's body in decent shape, i would say you can get atleast 250k miles

CARFAX!!!!!!!!! with proper maintenance, current days, 200,000 is the new "100,000 everyone was scared of in the 50's-60's that year, that high, i would have to say majority were "highway" miles, and much better than city driving...if you like it, buy it, i mean ANY used car can have an unexpected occurance, such as transmission, engine....if the price is in the budget, also NEVER HURTS TO PAY THE 100 (OR WHATEVER IT IS) FOR A DEALERSHIP, DEALERSHIP, to inspect it, for current/ soon to be future issues....in my opinion.....and the SELLER should be comfortable with this, if you inform them (inconvienent), so they may choose not to sell to you/ hiding something....it is routine for dealerships, and for car-lots to undergo that.....