Banks cold air intake

You will likely never recover the cost.

Wonder why the manufacturer didn’t open that intake up?

Still negotiating the price but it's $300 shipped
Not looking for mpg but if it works with getting a bit more power then I'm ok with that.
We travel to higher elevations and not sure if it would help.
Seems the 8.1 is terrible on power above 5000'

What sort of filter does it use?
Generally speaking Banks stuff is over priced and over hyped. I seroously soubt tou will see any difference.
Remember your motor is nothing more than a giant air pump. To achieve anything you need to work on both ends. More air in is useless unless you get the air out.

I contacted Brazels and got the UltraPower tune on my ECM for my 8.1L Workhorse. Since we almost exclusively traveled in the Western mountains, above 5000', and always had a toad, I asked them to reprogram the ECM for more power at altitude when towing.
This made a huge improvement and I would do it again in an instant. I did not go with a cold air intake, headers, or any other modification, and do not feel they are necessary. The only modification that I did make was to install the Taylor Extreme silicone plug wires, with the heat shields, because of the fact that plug wires on the rear cylinders failing were a known issue.
The UltraPower did not have any affect on my mileage, either increase or decrease.
I did make one other modification that I should mention. I cut the "tuba" air intake horn, turned it 180 degrees, and reattached it facing backwards. This did away with a problem of the intake sucking in water during a heavy rain.

It uses a KN filter

I heard about the water intrusion issue
I wondered if this cold air intake would solve that issue or maybe make it worse
I think I'll pass anyway
I like the idea of the Ultra power tune better
thanks

Banks may be somewhat expensive but I've had good luck with his stuff.

I contacted Brazels and amazed at their claims,
Gains of 60 HP and 70 lb-ft TQ
They said the cold air intake wouldn't make much diff but they suggested their spark plugs and would make a bigger difference
Wires
Kinda pricey for a flash but if it works then it's all good.
Flash

I use the Taylor Extreme plug wires with the GM heat shields and for 50,000 miles I have not had any issues with plugs failing or wires burning.
Plug heat shields
Taylor Extreme Plug wires
The plug wires can be found online at several different websites so I am sure that they can be found cheaper.
I didn't believe all of the hype about added HP but I did notice a definite increase in performance, especially in the mountains.

After-market engine "fixes" mostly are good at just one thing: Getting money OUT of your bank account. That goes for oil and fuel additives too.

The best thing you can do is keep the original equipment in good working order.

GM would not have put on an air intake system that harms the engine performance.