Do you have just one main listening spot?
Or is it a theater room or living room with multiple coaches and listening spots
If the first then the center channel for the HDI lineup is good any center channel will do or like
@shadyJ said you can skip one and save some money
The HDMI towers are serious performers for the money but so are the Arendals the Arendal does have the better center channel but that's only if you have multiple seating positions
You also don't have to have an identical center channel. Unless you like aesthetics. That only matters IF all 3 of your front 3 are identical towers or bookshelves aligned vertical at the exact same height for each speaker