Ideally an intank "pusher" pump of the proper psi would be the best bet. That said there is nothing inherently wrong with a "puller" pump located at the engine end of the system. When I first started working on cars virtually all of them had the pump located on the engine block driven by a cam and those systems worked just fine so long as the fuel line from the tank to the pump had no leaks. The problem, if you will, with the CRD system is 1) diesel is a bit more viscous than gasoline hence requires a bit more omph to pump and 2) the quick disconnect fitting on our fuel lines, particularly those above the fuel tank, are prone to bleeding air into the system due to the slight vacuum or low pressure in the line from a fuel pump at the engine end of the system (e.g. they seal ok only when fuel is under pressure). IMHO if you don't have air in the fuel filter head problems don't worry about it. If you do then a lift pump is a simpler solution than an in tank pump but you may have to cut out the quick disconnect fittings and replace with solid fuel hose. The Kennedy is an excellent pump and there is plenty of info on the forum as to how to install back near the fuel tank. On the other hand several folks have reported good results from a cheap simple Facet install in the engine compartment. BlackLibertyCRD has a good writeup on the latter at
viewtopic.php?t=24527 along with a nifty idea for how to easily tell if there is air in the lines. I have purchased Facets for my CRDs and stoutdog's but not yet installed. Note there is chat on the web about Facets being bad which was apparently true some years ago (high failure rate) but is no longer the case. They are pretty common on marine diesels.