528I or 535I Price?

If I were to purchase either loaded pretty well as far as premium pkg/sport w/navi and ventilated seats. What should the price approx. be? I put one together on the BMWUSA site and it was pricing over 60,000.00 YIKES!

In 1988 I bought a 735i for a little over $50k. In size, weight and power the 528 is roughly comparable and no more expensive even though it is in most respects a much better car.