I am looking to bump up my wife's 04 Jeep Grand Cherokee just a few inches, more for stance and look then anything else, but my local shop told me since the 4WD system I had, was the Part-Time 4WD Selec-Trac system and not the Full-time 4WD Quadra-Tec system, that even if I put a 2" spacer and shock lift on it, or tried to lift it at all, that I would have vibrations. Does this mean, that I can't lift the Grand at all without alot of mods to stop the vibes? I was also clueless on what size tire I could fit on the factory wheels if I lifted it. I guess I could fit 245/70R16 now, but just would have liked to run maybe 30s or 31s if possible on my 16 inch factory rims. If anyone could tell me what size that would be in metric measurements that would help too. Any advice on how to lift properly would be greatly appreciated. Just wanted to lift for looks mostly, but we do travel with this car and hit unimproved roads at times, but mostly wife will use for grocery getter, so not looking to raise it that high, and rather not have any rub with what I do run. I only know TJs, so since my wife got this Grand I am at a loss for good modification informaiton on it in regards to what will hit and fit and what lift will work best. Thanks in advance for any advice, information.