http://cgi.ebay.com/ebaymotors/NEW-I...Q5fAccessories

It looks like the mating surface is not milled in any way shape or form and will probably leak like a garden hose. Additionally who the heck actually makes this part?

 

Yes, I've tried them. Terrible aftermarket pump. I was suckered (suckered myself) into 5 of these. Bought them for $20 to $25 each. Installed two, both were returns in less than 6 months. I actually threw the other three away.

At one time, some vendor from overseas had these all over Ebay for $20 each. I believe these are the buyers of those reselling them. I've had the same problem with terrible aftermarket repoductions on the aluminum thermostat towers so I've gone back to OEM on both of these components.

 

The metal impellers could suffer from cavitation erosion as our coolant doesn't contain additives for this (silicates for instance).

There is nothing wrong with the later plastic water pumps from Jaguar, and they are since a couple of years also relatively cheap, so imho the best choice.