One of the really good tech guys at MSD told me years ago to always run a capacitor inline for any electronic ignition system/computer feed.

Makes perfect sense and protects the units from spikes caused by starters and battery switches etc.

http://www.summitracing.com/parts/ms...FaVZ7AodfikAVA

Cheap insurance

I would simply connect both power leads directly to the battery, just as the instructions say. The less gadgets the better, especially with electrical and ECUs.

That's a good point. I have done 5 of these Holley Systems and one of my clients, let his stereo guy install a new battery switch. But he runs the switch on "both", single engine, told him #1 or #2 battery only. I had to replace the delco style module,@ start-up idle was all over the place and shutting down until you tried it 3 times. Either, they did something when changing cables or voltage spikes from running on both batteries.
Is that considered a capacitor or a noise filter?

They are pretty much the same thing http://www.capacitorguide.com/filter-capacitor/ although there are different technologies available.

Where to buy Holley System and get some support? I know I can order from many places but I would prefer to buy from a place that is familiar with Mercruiser engines and boat wiring systems?

I can't imagine getting any better service than what Alex Haxby and Bob Madara offer. They have competitive pricing and will even supply a custom marine friendly base tune. The Holley system really simplifies EFI.

Alex Haxby, great support and better pricing than Summit

WHAT THEY SAID X1000! Great people to work with and amazing customer service. Extremely competitive prices.

UPDATE: So I spoke to edelbrock again, and the oval port pro Flo xt (part #71353) is suspended indefinitely for re design. The edelbrock pro Flo xt rectangle port, part number 71363 is still in production and available from many online vendors. For whatever reason, the oval port had distribution issues in the two rear most cylinders. The rectangle unit does not have this problem.

One of the interesting take-aways of PRI was the Holley fuel tank pick up solution.

http://youtu.be/4rG97UuVgmQ

Bob