2006 Mini Cooper S John Cooper Works GP, better known as the GP1. One of only 415 imported to the states. $17.5k seems a tad high to me but when only a handful come up for sale each year it’s hard to really value these. It’s right near my Aunt too!
It’s the ultimate iteration of the R53 Mini. 215HP, limited slip differential, 100 lbs saved compared to the standard R53 by means of a rear seat delete, standard AC delete (it was a no cost option to add the AC back), and aluminum suspension arms unique to the GP.