High-flow cat pipe only for CTS-EXH-DP-0015 THIS PART IS MADE TO ORDER, PRODUCTION TIME MAY BE UP TO 10 BUSINESS DAYS To remove the CEL that will occur, proper tuning software must be used. CTS Turbo recommends choosing a High Flow Cat for the sake of our environment! Use of stage 2 software upgrade is strongly recommended. NOTE: not a turbo-back conversion part. Only use as replacement for existing parts. Stage 2 software is required to avoid check engine light.