Emission Systems And Parts

My car is a Black 02 corvette convertible, custom exhaust, custom seats & covers, custom body kit as well and it's now got 53000 miles, i'd like to know when's a good time to sell the car before it loses too much value? i've had some recurring problems the past year and half, one of which we just now figured out and i think i now know what the last one is, if i fix it it'll be the first time i've had it that it ran perfect with no grinding or rattling marbles sounds. but the mileage concerns me and i'm about to take it from vegas to boston and then back as well, i'd like to upgrade if i sell it but i know i wont get near what i paid ($38000) in Dec.04 for it.

I really love the car but i want something with lower miles so is it best to sell it privately to maxmize the amount i can get for it now?

and my credit is garbage so normal financing options dont apply to me i've got to use cash on a trade in.

please help
corvette lover