If you want to spend less and get a used pump, there are many Bosch pumps that will do. Mine is from a VW Bus. It has the same dimensions, in and out fittings, and only varies in having nut wire connectors rather than spade ones. I only cost me $70 and looked almost brand new.
However, when shopping for either new or used pumps, it is tough to sort out the pump specs, not only the output, but the in and out fittings. Be aware that even though various aftermarket pumps will state that they are good for the fiat spider, many do not actually put out sufficiently. If the maker does not state the actual output, beware, in my opinion. The problem is that the manufacturers do not want to make a zillion pumps, so they "bracket" heavily, and often end up stretching the applications.
Similarly, Bosch themselves replaced the multitude of pumps they made over the years with just a few pumps that "bracket" many others. This handy table explains what most of the original numbered bosch pumps put out and what the modern replacement pump puts out.
http://www.leicestertr.co.uk/Part%20Num ... /pumps.pdf
Using my original pump, it seemed to me that ideally, we need a pump that sustains 300 kPa (system pressure), but if your engine is stock like mine, I found that the next "bracket" down, which is 250 kPa works fine. Even that might be overkill; I don't know. But the table is revealing, and it was the only thing really helpful for me in evaluating a minefield of aftermarket and junkyard pumps.
For what it's worth
In the past we have always gone with the bosch pump but In doing a little online shopping I've stumbled on a couple of other pumps. FYI, this is not a daily driver and total miles per year are a few hundred at most.
