When installing REMUS axle-back and cat-back exhaust systems or catalyst delete tubes on vehicles which are used for closed road driving, it is advisable to tune the ECU for a maximum gain in performance and to ensure that the CEL does not come on. Customise your Honda Civic Type R with the look and sound of a Remus Performance Sport Exhaust. I have a fk8 type-r exhaust ready to be converted for my 2018 Civic Sedan .It's in pieces right now and i measured all the piping .Honda also always makes the exhaust tapered (in some way) .After the split on the fk8 exhaust the OD goes to 2 times 50mm (2").Because exhaust gasses cool down ,they take up less space and the OD doesn't need to be Honda/ Acura expand. Civic Type R FK8; Civic Type R FL5; Civic (10th Gen) Civic (11th Gen) CR-Z; Fit; Integra Type R; RSX; S2000; Mazda expand. MX-5 Miata (NA, NB, NC) MX-5 Miata (ND) Mazdaspeed3; Mitsubishi expand. Evolution VIII; Evolution IX; Evolution X; Nissan/ Infiniti expand. 350Z; 370Z; G35; G37; GT-R; Q50; Q60; Nissan Z (RZ34) Toyota If you own a Civic Type R and want to add the OEM quality with an aftermarket sound then the Remus cat-back is a must. It features an aggressive street sound with choice of triple tips. The main piping diameter is upgraded from the OEM 60mm (2.36 inches) to a full 76mm (3 inches). kRiucLx.