BC Racing ER Series Coilovers for 2012-2016 Porsche 911 NA RWD (991)BC Racing ER Series Coilovers for the 2012 2016 Porsche 911 NA (991) put race grade adjustability in reach of the serious track day driver, with independent compression and rebound tuning at every corner. Every kit is extensively tested on the 911 NA 991 chassis and refined until it balances ride quality with performance the reason 911 NA coilovers from BC Racing are the best selling adjustable kits in their segment worldwide. ER Series kits run a