Just ordered 28i. Mileage varies by driving habits. Test drove both 28i and 35i and found minimum difference between both models. The advantage of 60hp and 40 torque difference will kick in at very high rpm. Again it is only my personal opinion. Try test driving both models without identifying them. I have no regrets buying 28i. As for delivery times, my order that was placed one week ago on Nov 25th will complete production on Monday, Dec 3rd and I am expecting the car within a week from Monday. My dealer said they have been getting the delivery in 11-12 days from the order. For trade-in, do ot bring the trade-n until the sales terms are finalized and not yet signed. This way dealer cannot mixup the sales discount and trade-in value to confuse you. Any time you bring a middleman, you and the dealer both are losing money. Instead submit an offer to multiple dealers and go with the best offer.