3. Alien Head Full Exhaust

What good is an intake kit without an exhaust to match? Fortunately, Brock’s hooked us up with one of his Alien Head full exhausts, too. Available in either polished ($399.95, shown above) or black ($499.95) versions The 12-inch megaphone muffler features a 2-inch outlet for increased exhaust flow and a deeper sound. It’s also designed to work with the stock foot pegs and provide maximum ground clearance for those who’d rather stretch and lower their Groms. Since we’re more concerned with performance in this application, let’s talk numbers. According to the Brock’s Performance scales, the stock Grom exhaust system weighs 11.0 lbs. The Alien Head system? A mere 4.15 lbs. That’s a 63% weight savings. As for power, the Alien Head system made 10.07 hp (vs. 8.57 hp) and 8.17 lb.-ft. (vs. 7.85 lb.-ft.) on Brock’s test bike. That’s 17.5% more power and 4.1% more torque. We’ll gladly take those gains.