I was thinking around 11,000 to 11,500. Here's the KBB
Kelley Blue Book
Common problems are the trans in the GXP's, many get rebuild by 80k and most do by 100k. It is the same trans as what's put on the GTP's but the GXP has much more power, stock vs stock.
Other than that, the common problems are similar to all other Grand Prix's 97-08, mainly a bunch of little things here and there. I don't own a gxp, and I'm not sure if there are any gxp specific common problems or not. There are a good number of GXP owners on the site, hopefully they stop by.
