Advice for negotiating?

Inspector71

In 2006, I bought a red Nissan Pathfinder LE. It is loaded and now has 23K miles. I wanted a 350Z but my wife said no way. Now she tells me I should have bought the Z because I don't drive the SUV very often (gas mileage, size of vehicle, etc). I put no money down and financed everything. My payment is $643 a month which is $243 dollars a month more than I wanted to pay. Okay, Nissan says they want my low mileage Pathfinder and will trade for the 370Z. I have one picked out whose base price is $28K but marked up to $31+K. It wouldn't be worth it for me to "give away" my loaded Pathfinder to absorb a payment in the same range. What is the bottom-line price I can realistically expect if they really want the SUV and I stick to my budget...this time? Thanks. I have an appointment this Friday.