Chris,
I would doubt you need to upgrade brakes...I assume you mean pad compound? Other than pads, some DOT-R compound rubber would make a world of difference over street tires; they're not meant to be tracked. The Boxster and S have far more capability than 97% of the drivers...spend your money on track days and/or driver's schools.
By all means, fax or email John Ruther your instructor thoughts...it's the only way to keep everyone up to standards. John is the owner Northstar Motorsports in Barrington and can be reach at:
john@northstarmotorsports.com
Hope to see you out in the future...it was good to knock the cobwebs off!