You are going to be in a pretty small group running a dry sump, so I am not sure how many answers you will get. I don't have one, but I investigated getting one for another project, so I will share what I can to help you.
Most systems run off the front of the crank. Some run off a cam, some run off the flywheel, but these are exceptions and available only on the most popular of engines (aka the small block Chevy). The drives are usually by toothed Gilmer belts, although a few employ a poly rib serpentine belt. As with everything, belt tension is very important.
I have never heard of CFM, yet, although we share a common language and interest, as we are on near opposite sides of the world that isn't entirely surprising. My advice is to look for used units for sale (end of season is usually the best time) and see if you can find any pattern of problems. Are they all being sold with stripped threads or a bad bearing? This would tell you something.
Typically, dry sump pumps are made to the highest level of quality because their failure causes massive amounts of damage. At $1000 or more, a dry sump pump is a significant investment, but when it is supplying a $25,000 Late Model engine, not many people are going to take a chance by saving $200 on an unknown brand.
Hope this helps and please post up pictures of your project.
