Howdy -
There are a number of different ways and options for you to lower your call.
lowering springs
M030 kit
Boxster Sport M030 Suspension
from someone in your region.
H&R sway bars with standard shocks/springs
And there are a number of different opinions on tires.
try the search button - top right.
We have similar color and miles on our "new" cars. I have 18s on mine and am thinking of lowering/firming the suspension as well.