Re: 15" rims on a WK
No the worst that will happen is you might damage the wheels sooner then an small wheel. If you look deep in to off roading and many competition vehicles 17" is the ideal size.
-Kyle '05 Dark Khaki (PJT) WK Limited 4.7L V8, '08 Overland Front End, Custom Exhaust, 245/70/17 GY Silent Armors, Bilstein 4600s, K40 Calibre DL Radar Detector/Laser Diffuser, CB.
Wife's Jeep: '06 Jeep Liberty KJ 4x4 2.8L CRD Diesel