I am hearing good and bad things about my C91 sporter I was looking to trade it for a handgun so if you have any ideas or tips on c91s let me know

Does it shoot well?
What are your issues?

Century has a well earned reputation of "spotty" quality control.

If your C91 has a good bolt gap (without a ground bolt) that is a good start.
If you can insert a magazine and pull the charging handle without needing a friend to help that's good also.
If it feeds, fires, ejects, and hits a target reliably and repeatedly then you've got a good one.

If it's a good one then I'd hang on to it and shoot the snot out of it.
(Or at least as much as you can afford to)