X2 / X4 Weller Racing ECU & HMF Slip-On Exhaust October 31, 2018 by Matt Robinson No comment(s) Accessories, How-To ECU, Exhaust, How-To, X2, X4 3596 Installed the Weller Racing ECU flash and HMF Quiet Core Slip-On Exhaust on the Yammer Hammers X2 Related