Any aftermarket exhaust will help with the heat since you're eliminating the stock catalytic converter, all should be similar in power since there's no real "magic" design that's going to provide huge gains on these machines by simply installing a new muffler. Our Q6 Stainless Steel slip-on muffler is a great choice if you're looking for a quiet, maintenance free aftermarket exhaust- it's only 3-5db louder than stock and only 1/2hp less than our louder L2 version. No fuel controller is necessary with basic bolt-ons like a muffler and filter, but there are more gains to be had with one- especially if you get the PCV with the raised rev limiter. There's a bunch more info in this thread, including dyno testing with and without our new header-
http://www.wildcatforums.net/forum/wildcat-sport/35690-speedwerx-new-sport-trail-header.html
There's other threads discussing it on here, but the updated '16 firewall and additional heat tape and/or venting will help eliminate any potential melting issues as well. We had our 15 Sport with the Q6 and Stainless Header out at the Rally on the Rocks- no venting, and using the original firewall with a piece of heat tape approx. 12x18 over where the stock foil was and had no issues with heat. The biggest test was on one day when it was 90°+ and sunny, we were in a slow group that was going maybe 5-10mph max for a few hours with no opportunity to pick the speeds up to get some air flow- the firewall behind the passenger seat with the heat tape was warm but not bad at all, and the "headrest" panel above the firewall and the area between the seats that had no heat tape felt very hot, but still no melting or deforming at all- and that's with no roof or anything to shade it from the sun either. On cooler days or where the speeds were higher, it did not get unusually hot anywhere. Your mileage may vary, but that was our personal experience in almost a worst case scenario.
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