Should I rewrite my fanfic?

Concerning my crossover fic Inheritance of the Slashers:

First, before your respond, it would be best if you first read the eight or so chapters (they're not that long).

Now, I know for a fact that the dialogue, explanations, and showing-rather-than-telling in those first eight or so chapters is incredibly mediocre, but I would like to know:should I just rewrite the first eight chapters and leave the rest of the story be, or should I completely rewrite it and leave the original so people can compare the two?

I would suppose it depends on the extent you intend to rewrite this. If you're just correcting typos and adding descriptions where there were previously none, then I wouldn't bother rewriting the rest. But if you intend to change what happened, add in plot twists, and leave in Chekhov's guns or set up brick jokes for future use, I would go ahead and rewrite the whole thing.

Well, the thing is, there was a lot of unexplained OOC-ness in the first eight chapters (like Jason Voorhees and Michael Myers suddenly talking), more telling than showing, and problems that cluttered up later chapters (for example, in chapter eight, the meeting happens and previously, the slashers were going to bring up the Uni-Silo; however, I forgot to bring up the Uni-Silo in that chapter and it instead got shoehorned into chapter 15/16).