Here's some info you might consider-- the C4 has a retrieve ratio of 6.3 to 1 while the C3 and C5 both have a ratio of 5.3:1. What this means is that they have a little more power while the C4 has a little more speed.

Unfortunately, the C4W (retrieve ratio of 3.8:1) isn't available in the 6500 size. It would be a good reel for big fish that you have to move.

Does the retrieve ratio make a difference between the 3,4, and 5? Probably not in real life (with exception of the 4W). If you're going to be casting with the reel, the C5 is probably a better choice because of the extra balancing/finishing work.

Good luck,

Keith