My opinion is the same. Pulling the baffle with these stock exhausts really doesn't make a big improvement in power. The most restrictive part is in the inner core of the silencer. Although in my opinion, it sounds more like a broken lawnmower than a popcorn machine lol.
Difference between spark arrestor and baffle - A spark arrestor is typically a metal screen to catch the sparks and keep them from exiting the pipe while hot. A baffle is a formation of metal that restricts the exhaust and reduces the sound output. Some are just a reduced size in the outlet, and some are more restricting like the one in our stock exhaust, which has a spiral-shaped end to further reduce sound.
The stock one is actually a combination spark arrestor and baffle.
And yes, you will have to rejet if it's currently using stock jetting. In my opinion, they need rejetted right out of the box completely stock. They come from the factory borderline lean to pass emissions requirements, so an increase in flow will be enough to push them over the line of being dangerously lean. Aside from that, you'll never see power gains unless you have the right fuel ratio so it doesn't make sense to mod it without jetting.
I'm not sure where you ride, but if you ride in areas with a lot of housing, or sound output restrictions, be careful about what aftermarket systems you buy. Most limits are 96db or less, and my HMF rang in at 102db with the spark arrestor out and no quiet core. It sounded awesome and the power gains were good, but it would be obnoxiously loud if you ride near houses or in places with sound restrictions.