regear will would be the best for larger tires to help put the RPM back where it needs to be saving your transmission from endless gear searching. part time will marginally reduce spinning mass might save you some gas but, you basically down to one wheel drive. handling is different. power adder will overcome the sluggishness but, still not ideal as the trans might still search for a gears on the road.
ECGS has always provided me with great service/pricing.
Google Nitro 4.88's and you will find ECGS usually at the top of the list in terms of lowest price. We are lucky to have them so close. To save on cost, lock your axles if you have a lockers and pull the axles from the housing. Pop the driveshafts and thirds out and put the thirds in buckets. Be careful. The rear is 80lbs, the front is 66lbs and will certainly smash fingers if you aren't prepared. Cost is $1500 to $1600.
I would also recommend regear, part-time, and finally turbo/supercharger.