If the dealer is offering you a trade it is pretty obvious you would somehow lose out one way or another...you did the right thing to hold on. Over the years I occasionally thought about trading 'up' .Today the right 308 is priced over 328/348/355/360/even 430 (F1).Has a long way to go to rise above 458 but i guess it will probably happen within the next +/- 5 yrs.However i will most likely never make the trade. 550 is the V12 i would like to also own,but if you no longer wish to keep her then you have quite a good range of great cars to choose from. I would go for a 430 MT if the numbers eventually work.