With the JK, they curved the windshield to try and help with aerodynamics as well as rock chips. I've had several rocks hit my windshield at highway speeds and I haven't had any chips or cracks. You should try one of those guys on the corner of a gas station that fill in the chips. It may be cheaper and prevent the chip from turning into a crack.
'09 X Unlimited, 4WD, auto, half-doors, soft-top
RC 2.5" Series II BB, JKS Quick Discos, JKS adjustable front track bar
15x8 Unique 297 (Soft 8), Goodyear MTR/Kevlar 35x12.50R15
5.13 gears, ARB front locker, Currie front shafts
Bushwacker flat flares, Rubicon rails with steps added