Yep i've got one on mine - see picture here.
Let me tell you it is not a simple 'bolt-on' addition. Probably 20 man-hours were spent with wiring and bracket making, testing and re-testing and deciding on the best location(s). I used the latest davies craig one.
The pump/controller works very well to cool down a car after turning it off.
The ewp runs for about 2 minutes after shutting off the car, then start up again for 30 secs for a second round of cooling after temp. rises slightly.
I have spent alot of time to get it working in a race environment.
I don't know why people are always saying 'but what if it dies?'. What if you lose oil pressure? Pull the car over and get it fixed!!! I've had it on for 2.5 years with no reliability problems.
There'd be little point putting it on as a supplemental water pump - flow rate isn't the problem with the mini cooling system, it's getting air through the damn radiator that's side-mounted!
This becomes more of a problem with no motor-driven fan as thermofans don't pump as much air. Some guys run auxiliary heaters / radiators at the front of the car to drop the temp. another 5 - 10 degrees.
The car loves to rev, and if you take the alternator off it goes even better.
I'm using a thermostat blanking plate (ie. thermostat always open).
Feel free to ask me any questions - if they're specifics PM me.
Rob