A longer wheel based car will handle better and won't turn around quite so quick when exiting a corner. As for all the rest do you plan to race the car any or do you just want a good performing car that you can cruise around in. As for the long trips, I never did find one that I enjoyed driving a long ways. And for a reliable engine with umph in it, you can have stroker small blocks, big blocks, and a number of combinations depending on just how much umph you want. The more radical you it is built out, the more likely you are to have a problem.
Also if you are buying a completed car from someone, have a person that knows the car go with you and look it over very well. Some of the builds that are for sale are not well built and you will have problems. Some are better than the factory new cars. You just need to know what to look at and for. Also if you are buying from a person who has built the car, have him go with you and take it for a drive and see how you fit in the seats. Not all Cobras have the same room and leg room.
Ron