Duuuuuuuude. Relax. You don't have to buy everything under the sun just yet. Get your rig, drive it for awhile, and decide what mods you want to make.
But let me get this straight. You couldn't make up your mind between a 2.5" lift vs a 4" lift because you don't do much hard core wheeling. And now you want to flip your u-bolts for ... well, you kind of lost me. Yeah, it is a decent mod, but if you aren't going to be wheeling it that much, what's the point? If you plan on scraping your axles over rocks all the time, then yes, flip those u-bolts. If you are just going to run dirt roads, wait awhile.
It seems you agonize over every decision. Again, relax. Like I said, you don't have to buy everything just yet. Enjoy your rig for awile and then plan out your mods. If you feel like you need to get a u-bolt flip kit down the road, they will still be available.
With all that said, Mark is a forum member and I can't see him selling junk. On the flip side, the 4+ stuff MAF sells has a great reputation. I don't think you could go wrong either way.
Good luck with ALL your decisions!