I'd definitely suggest denim needles.
I'd also recommend finding a jeans foot if there is such a thing for your machine. I feel like it makes a great difference in my machine. A straight stitch plate might help too, but isn't necessary.
You'll also want some sort of level compensator. (But you can make shift that.)
I'd give it a try before buying anything new. Are you wanting to make these for production to sell, or just for yourself? Almost any machine is going to be able to handle denim, though you'll possibly have to hand turn the wheel over the absolute thickest bumps (the hem of the edge, where you get 8-12 layers). If your machine can't do it, then look into something new. I did jeans on my Walmart Brother, and the experience wasn't nearly as nice as on my Bernina, but they did get done.