You better be picky. You'll pay a lot for the car and you won't know what it has been thru if you're not "picky". If the car already has a swap, someone prolly already drove the shit out of it. Just beware of that. If I were you (and I know I'm not) I would do my own swap or have a hop do it (whatever. as long as you were involved somehow) That way someone is held accountable for the work and you will know what it had been thru.

Just my 2 cents