I guess it depends on how long he wants to keep the car. If you're paying for it, may as well just get a kit, cuz you'll probably trade it eventually. If you own it, go for a swap, but it's going to take that much longer to save up and prepare for the turbo. People who own cars tend to hang on to them longer because it's not as much of a burden.
As for me, this is the third honda I've 'owned'. So it's just more of a toy, but one I can't get away from because I have a sickness. I'm completely nuts.
As for how much to let it go for...

I dunno. There's $3 grand worth of Misc. upgrades going in soon. Not to mention typical maintenance.