Congrats on your first PDX! Are you an SCCA member yet? If not, let me be your referral
I can send you my name/member number and save you $15. Face it, you know you're going to be hooked, might as well sign up now ;
Couple notes: magnets will do just fine on a road course. I've yet to lose one.
Also, I love your "save my expensive contis" comment. The RS-3's will blow them out of the water on a road course. You're going to LOVE them. For 140+ TW street tires, they're about as good as it's going to get for road course events. They take heat and beg for more. Use them for autocrossing too (assuming you're probably running STU?)
HP+ are still going to beg for mercy. You're in MN, so Road America? I would absolutely recommend changing your brake fluid to at least Super Blue, but I would highly recommend stepping up to Motul RBF600. I autocrossed for three years and got very good at it before taking my Z4 to Mid-Ohio for my first track event. I had HP+ pads on it on street tires, oem brake fluid. PDX's are like autocross in slow motion, so if you're any good at autocrossing, you'll quickly start pushing your car hard at the track. I did, then my brake pedal went to the floor coming out of thunder valley. That's an eye opening experience in a daily driver. Long story short, if you're doing HP+, bed them in correctly on new rotors, and switch to Motul RBF600 fluid. Or, conversely, don't brake the ever living piss out of your car.