Just as a data point,
I got the Van's FWF kit, but ended up fabbing alot of my own hoses. First many were not long enough, I think because I have the long mount...which Van's sold me. For example, the line for the FP to the FW mounted pressure transducer was too short. Ditto on the fuel feed lines. I made my own oil cooler lines because Vans lines were too short, in my application to get a nice stress free installation. In addition, I wanted my oil lines firesleeved because bare braided steel is a great abrasion source for anything near it, and also, if a small fire were to break out, I did not want it to become and oil fed fire. Once you get the tooling for the SS band clamps, doing the firesleev is really pretty straight forward.
I am not sure I would go the FWF kit route again, I would probably just make my own hoses from the git go. The electrical cables are nice though, and frankly I think it is a huge pain to make the big cables for things like the starter. Other than the large cables, the wiring harness kit was a not cheap way to end up with alot of tefzel wire in my case because I ended up with different wiring and routing needs than it was designed for.
The baffles are nice, plans to make them yourself are out there, and I toyed with the idea of making them out of a more tolerant aluminum...to avoid cracks. In the end the baffle kit was just too easy to use and I used it. I will watch for cracks but I wonder if it might make sense to construct the rear baffle pieces out of a thicker piece of 5052 to take advantage of that alloy's fatigue resistance.
I did not end up using the Van's oil cooler. It is great I am sure, but in the end I wanted the quality of a Stewart warner. If you ever look at them side by side they just seem to come from two different planets. I am sure the Van's Niagra unit is fine, but for a few hundred buck, I just felt more comfortable with the Stewart warner, and I had saved the money in other places.
Strangely, I also had to re-order control cables, because the ones in the kit were too short. Again I chalk this up to using the longer engine mount for an O-320, but I was a bit dissapointed that I got the wrong stuff when Vans was aware of the setup.
The control cable mounts for the carb and prop governor were awesome, and I cannot imagine an easier way to mount the controls on the business end.
I know scores of folks who have successfully used the kit on a more traditional O-360 or IO-360. Seems not to matter if it is a Lycoming or ECI or Superior. Most of the engine shops, and for sure Mattituck and Lalonde, know which servo arms and other setup variables you need to work with the Van's control cable brackets, so if you tell them what you are doing they can configure your engine for ease of use.
You may want the exhaust to be a bit different too. If I did it again, I would get the muffler/heat system. Those who have it report ultra toasty heat...and I live in Minnesota. I hope that my dual muff crossover will be adaquate.
I would think you would want to make your exhaust, wiring, and other decisions, and then see how much of the kit you still want. Vans will let you add and delete items.