Should I Get An Exhaust?

I have $350 and I’m not sure if I want to get a Big Gun Evo exhaust, or a GoPro Hero 4 Silver.

My 4 wheeler doesn’t like to idle under water and I was told that a Big Gun or HMF exhaust would help. I do a lot of river and pond riding, not much mud so its mostly just water I’m riding in. When I go slow or let off the gas while my exhaust is even somewhat under water the engine seems to die. My atv has shut off under water 2 times but i installed a valve on my exhaust that immediately closes when the atv is shut off. so im not worried about water getting into the engine.

If anybody thinks it just wouldn’t be worth it to get the exhaust I’ll be getting the GoPro, but if you think the exhaust would help then I’d get that.

Thanks in advance