I need to know which is the best exhaust for my Polaris 850 XP I've been wanting a HMF swamp XL series pipe but I just found out HMF don't make the full exhaust I thought that a FULL system will give the bike more Horsepower so which is it I know Big Gun makes a full exhaust for the XP so which exhaust do you guys think is best full or slip-on and what make exhaust is best like what make exhaust gives you the most HP it could be any exhaust from fmf to hmf any which is best