AST 5300 Series Coilovers | 2015-2018 BMW M3/M4 (RAC-B2106SD)2015 2018 BMW M3 M45300 Series Coilovers by AST Are you the most serious person on the race track? Get to a winning setup by using all the options that our 3 way adjustable dampers have to give. All adjusters work completely independently. Once installed the shock absorbers are easy to set, highly reliable, and require low maintenance during the season because of the high grade of materials used. Tested on tracks like the Nrburgring, Zandvoort, Imola,