What intercooler do you run? A bunch of guys ran into this issue in my club last season. All of them had front mounts (Neuspeed, Forge, ARM) and all of them switched to OEM location with great success getting temps back down. The front mounts block too much air and don't allow enough to get into the rad and engine bay causing cooling issues. If you just want a cheap way around it, empty your surge tank with a syphon or plunger and fill it back up with distilled water and some water wetter. I run a 60/40 water/coolant mix in my racecar and have never had an issue. So just adjusting your coolant/water mix can help alot.
EDIT: IF YOU DON'T WINTERIZE AND STORE YOUR CAR FOR WINTER YOU MUST CHANGE THE COOLANT BACK TO 50/50 WHEN WINTER COMES!!!!!
Edit 2: How did you like the 17z setup on track? OEM master? OEM rear brakes?
I am running all of APR's supporting mods for the K04 kit, so their intercooler, which is a factory location unit. I as well am a firm believer that a front mount does block the rad too much as well. That being said, I think I'll use a different mixture next week when I am out at Laguna Seca.
I'm in California, no need to winterize
For the price, I love the 17z kit. I was able to piece it together for no more than $400, so less than a third of any aftermarket BBK. Largest cost has been the carbotech pads, but I am not equating that into the price of the overall kit. I just run Stoptech's aggressive rear pad, and toss my carbotech pads in for the track. I love it. OEM master.