Speaker jumpers

At the least I would use the same cables as your speaker cables, just buy an extra length or cut some off the ends of your current cables. Anything fancier doesn't seem like it would offer a benefit. I did notice an improvement when I replaced my flat gold plated brass jumpers with short lengths of speaker cable.

It all depends on what is there now, really. And what you plan on replacing it with.

@fsilahua - it's funny, I wondered about all those parts in my modest system, spent some time and a small amount of money to DIY upgrade them, and was rewarded with a significant improvement in sound.

It is pure folly to stress about whether or not your system and its parts are good enough. That way ends in a neurotic vortex of anxiety.

But a healthy curiosity and a desire to experiment can be incredibly fun and improve your system to boot. That said, just because some of us like messing about doesn't mean that you can't just enjoy your music reproduction system as it stands. Just decide what you 'want' from this hobby and gravitate towards those that share your values. It doesn't mean anyone is right or wrong, it's just that this is supposed to be fun, so if there's an aspect you're interested in, chat with those who have explored that area and take all the naysayers with a grain of salt. Many if them haven't even experimented with what they are knocking down.

Chat with the cable manufacturer. They may be able to make a pair with longer tails on the amp end