You can ask $5k, but who knows if you'll get it. It won't hurt. Depends on the market, time of year, etc.
I had a really nice GTP, fucking SUPER clean, probably one of the nicest Grand Prixs in Columbus. It was seriously spotless inside and out, looked like a brand new car. Not a single problem, a few mods (which don't add any value btw), great all around car. But it was a '97 with 135k miles, so KBB said it wasn't worth dick (I think they valued it at 2700) and I didn't think anyone would pay what I would have asked for it (over 4k). So, I ended up trading it for a truck that was worth more, then selling that a few months later.
I suppose it would have been worth a shot to try and sell it for what I thought it was worth. I guess what I'm trying to say is that a car is worth whatever someone is willing to pay for it, but more often than not they always go by NADA or KBB. If you aren't desperate to sell it, ask $5k and see if anyone bites, but don't be surprised if you end up sitting on it for a while until you lower the price.