The original pump was an ES 40105. The latest replacement is an ES 40135. It has a little higher pressure. Make sure you buy the latest.
As for the ES-00102 cap, $113.75 sounds a little steep, but it is all made up ready for install. The guy who assembled it wants to get paid, too. The most expensive 22,000 uF 25 Vdc cap I found on Digikey was $26.89.
For a cap the major parameters are capacitance and breakdown voltage. For specific applications material type and construction can come into play but for this application I think a garden variety 22,000 uF electrolytic of an appropriate voltage rating would suffice. It is a 12 Vdc system. I don't know the voltage rating of the Van's cap but IMHO people usually cut it too close. For example, I don't think I would install a 16 Vdc cap. I would be more inclined to derate some and go with at least a 25 Vdc rating but that's just me.
If you aren't seeing noise problems then you probably don't need it. On the other hand an ounce of prevention is worth a pound of cure. Noise can manifest itself in multiple non-obvious ways. Maybe you don't hear anything but maybe it is degrading a VOR signal. Or maybe it is only a problem on certain frequencies. Or maybe it is degrading the performance of your ADS-B receiver. Etc, etc, etc. These pumps are electrically noisy. I'd go ahead and plan on putting one in.
