02 Sentra SE-R because of lack of reliability. Needing a SECOND engine replacement after only putting 15k on a new engine from Nissan. Car only had about 70k miles on it.

02 TL-s Transmission going out is always in the back of my mind. Main regret is not waiting a little longer for s2000 or CL-s 6spd prices to come down a bit. Still a great car tho with decent mileage for its size.

Only car i don't regret and will pick up in the future is another 6gen civic.