If someone criticizes you on a dumb question on here, ignore them as they are know it all's, not that there is any one here or anything lol. The best thing to do with the Big 3 as mentioned above, is think about what you are going to do to the quad. Such as, will you go into the engine for more mods? If so, then a Dobek probably isn't for you. If not, then a lot of people enjoy their EHS setup. If so, a PC3 or 5 is your best bet, as you can go to any authorized Dyno tester and they will be able to fine tune your set up. A big recommendation of mine is to do tires first, and then go from there. Some people save up and buy one thing at a time, and if you are to do the big three, and buy one thing at a time, the best thing to do is get the programmer first, as that is the limiting factor as Roadkill said when purchasing a full exhaust. Another thing people say is to get a sway bar or better shocks.