Use "TOUR20" coupon code and buy 2 GP4000S on probikekit.com right now, total comes out to $80.30. Will take 1-6 weeks to arrive, but at half price of what you were quoted it may be worth it if you've still got tires to use right now.
Find a buddy, buy 4 instead of 2, and the price each goes down to $35.50 ($142 for 4).