Wonko,
I stand corrected
I did a quick check on AutoTrader. There are seven 1997 Boxsters for sale in the US with over 100k miles ranging in price from $12,000 to $16,735 ( average price $14,200 ).
I had my buddy check and see what they are going for at auction and he said about $11k.
I would say that $11,250 is a great price !
Nick