GMB has proven to be a reliable choice. I bought a Flow Kooler water pump for my 4.0 back in 2003ish. Back then they just had a metal plate riveted onto the impeller and charged $120 for the damn thing. I bought it anyways because i always like to upgrade when i have to replace stuff. Shortly there after i bought a $25 GMB to replace the water pump on another jeep i had. It had exactly the same casting as the GMB when I looked it up. Flow Kooler merely riveted a piece of metal to the impeller. They also charged $100 more. It also offers a GMB water pump, which is rated poorly by users. The impeller always hits the block and it won’t work. The plate is riveted onto the standard pump and increases coolant flow. Although it was not tested, it seems to be possible. The Flow Kooler, (GMB), came with a thick and a regular gasket. In the instructions it said that if the impeller struck the block you could space it further with the thicker or regular gaskets. I used the thin regular gasket because mine did not cause interference. It’s still in my jeep today. The GMB pumps have this weird machined out area where the heater hose pipe comes out that is filled in with a aluminum plate and they are the only ones i see made like that and i have replaced a lot of 4.0/258/2.5 water pumps. Grease. Monkey17