McLexus

I just purchased a beautiful but mysterious ES300. I bought it from a dealer (decent guy) with 108,000 miles but received no service history and the last owner was long gone. It runs like a top; doesn't smoke; and sounds like a sewing machine. I have been reading with much interest, as much info as I can find on this model and make. I'm a bit spooked about the timing belt thing and am experiencing the well documented "dash-dim" on the tach and temp needles...I've driven Volvo and Saab for years but I can feel something special about Lexus...If I can't get any idea (the dealer isn't much help) about where the car is maintenance-wise, should I bite the bullet and do the whole timing belt & all fluids change for an obscene amount (at a dealer?)? I appreciate the objective help and advice from experienced owners and techs. Thanks again.