As some of you know, I am not too mechanically inclined and had a questions regarding differences between these two types of headers.

Currently I have this type of set up. (not my boat, just an example)
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Was wondering if there is a performance difference going to this type of set up or is it just for aesthetics?
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Main reason for asking.
Last time I had my boat out, once in a while when I gave it gas, it would studder and take a while to get going (not all the time, just sometimes)
Someone told me that the boat is burning too rich and I should take my engine cover off.
When I see other jet boats out there with the engine cover off, I see the headers over the stern.
Was wondering if I would have to put these on if I took the cover off.
If so, is there a performance difference.
I have a 19.5ft jet boat with a 454.

With my limited mechanical knowledge, I hope my question makes sense. lol
Thanks in advance guys.