undoubtly you guys can not read redneck.

. Since I am from the sticks I will try and read it for you.
He wants to trade his car in on a mach 1. His car has a bad oil ring or so (he thinks) and wants to know if the trade of 9k for the mach 1 is worth 21k, etc, etc.
yellowsvtcobra , first off your dealer is only quessing that it has a bad oil ring. It may be seals, guides ( Mark gave me these suggestions on mine).
Here is some great advice since you are requesting some.
Keep your cobra, fix the problem you have on your car.
If you are trading for the muscle, then the cobra is what you need.
My problem is with this post is...... if you know your car has a problem, then fix it or take a loss.
I cannot stand it when people push there problems off on someone else. it is not smart, it goes show your level of maturity. If you cannot fix or cannot take a loss, then you need to sell your cobra and get a nissan sentra.
good luck,
Rich