Everyone will have their own personal opinions on this one
I love my HMF Performance duals, nice deep sound. I personally wouldn't install a pipe without a tuner especially if you get an upgraded air filter. Tuner to me is worth it, at least you have the reassurance that you're quad is running at the proper level it should be. A little extra $$ to make sure your motor doesn't burn out is worth it to me, with the higher elevation where I'm at it was even more justification to get one to make up for the power loss......just my $.02 , G/L with whatever you decide to go with, You Tube is your friend to find that sound you're looking for, but I know that alot of the clips I researched don't do them justice in person.