Any advice from those of your out there that tow with a Grand Cherokee? I've just started looking into trailer hitches and trailers for my '04 WJ. It has the 4.7 V8 and full-time 4WD, but it is the Laredo so it doesn't have the HO 4.7. Should I get a class III or IV hitch? Do I need a transmission cooler, trailer tow (?), or synthetic axle lube as it suggests in the owners manual? I was looking at a UHAUL class III. Will this do the job? I'm think the Gross Trailer Weight will be around 5,000 lbs. Thanks!