I replaced my stock pump on my 05 Rubicon when the seal went at 139,000 miles. I did a little research, this seemed like a nice option over the OEM replacement, I had some extra cash on hand so I tried it out. Shopped around for price, had to purchase an aftermarket seal from Fel Pro, the instructions that comes with the pump says you "may need" two seals, but I didn't. I just bought the Fel Pro one because they seem to be better quality than the junk paper one that comes with the unit (you'd think for the price, they'd include a better seal as thats what normally blows first). The unit had some external pits and gouges on it, I sent pictures to FlowKooler, spoke with their tech rep. He confirmed this is nothing unusual as the housings are cast in the land of narrow vision and flying dragons, they assemble their pieces in house in CA. Otherwise, all seemed relatively similar to the stock pump when I removed it. Make sure you use some thread tape on the water pipe and go easy tightening it as stated in the instructions, it's easy to tell the housing might be fragile in that area. Some reviews said the water pump pulley bolts were not the same thread pitch but my original bolts and pulley worked just fine as did the fan. Clean everything really well, use RTV on both sides of the gasket, ensure you keep track of which bolt went where as they're different lengths (five in all), all in all the hardest part is taking everything else out of the way to get to the water pump. Stats on this thing says it reduced temps and pumps more water blah blah, I'm sure in a lab somewhere it may, I've had it installed for three months, this Jeep is my daily driver, and I take it off roading a few times a month, granted no heavy crawling, but I haven't noticed anything different. If I was to do it again, I'd pass on this and get an OEM pump. One big recommendation is while you're already in there and have all the other stuff out of the way, just replace your timing chain and sprockets. I literally got everything back together, turned it on to check for leaks and started hearing a knock in the front cover....two days later, took it all apart again (I was careful enough that I didn't have to remove the water pump) but still, hindsight being 20/20, and I've read in other areas, it's a simple job, just do it for the extra 70 bucks while you're in there. All in all, no doubt this thing is easy on the eyes, I'm sure it may help a tad off road, but our 4.0's run hot anyhow, keep your block flushed well and often, and just go with an OEM one unless cash isn't an issue.