That website doesn't know anything. CCA has nothing do with your electrical components. A higher CCA will be better for your alternator because the cranking should be reduced, therefor reducing the voltage drop in the battery, therefor reducing the load on the alternator.
The only thing you have to be conscious of is the height/dimensions so things don't come into contact. That's it. Anyone that says it could fry things has zero proof and is just repeating something their dad's friends brothers friends dad said. A 12v battery is a 12v battery regardless of its size. The CCA is literally the only difference.