im fairly possitive the XS5100 will fit your civic. it fits my Camry with ALOT of room left over. also, if you go with the XS (which i would), you have to get the XS5100R same with the Kinetic. HC1400R (reverse Polarity.) the + on the left and - on the right. XS whoops Kinetic in Performance no question. but price, Kinetic is more budget friendly. theres a vid on YouTube showimg XS compared to the competition. (kinetic) I love my XS5100R. im thinking of adding a second in my front battery compartment since i have so much room left. but idk if thats safe to do...