CFMoto 250 Mods

I've recently acquired two CFMotos, a 2008 V5 and a 2007 Qlink Legacy. They are pretty much stock straight, so now I'm wondering what mods I should do, and in what priority. I'm pretty sure the tires on both of them are the factory originals, so I'll be looking at something new, and sticky, if possible. (Both bikes have less than 5,000 miles on them.) We're surrounded by dirt roads, so these bikes will both occasionally see dirt, otherwise, they'll be on pavement (95% of the time). The headlights are the standard 35W bulb, so any upgrade to that would be better; I just don't know what my options are. The bike that I ride could use a power boost; it has to haul my 290-lb. carcass around. Is there anything I can do to these motors that will provide a noticeable performance boost, aside from an engine rebuild? I see a $99 carb swap out there, does anyone know if it's worth it? How about CVT mods? I welcome any and all suggestions!