Iowa shop owner spearheads new MWACA chapter and is determined to move aftermarket forwardAnnual revenue at Griffin Muffler and Brake Center is more than $750,000, driven by three techs, a service writer, part-time customer service representative and four bays. Iowa shop owner spearheads new MWACA chapter and is determined to move aftermarket forward By Rob Merwin on March 4, 2020 ‘If we can get a united front, we can elevate our industry to a higher standard,’ says Nannette Griffin.