IMHO, Cobra products just plain sux! They're cheap and built that way. The quality of the chrome is non-existent. They begin to rust as soon as you pull them out of the box. Jardine are quite a bit better, though not my favorite either. But, those were the only choiced I had on the VX800 I was working with. I liked the cobra's look better, were cheaper, so I bought them first. There was spots of rust on the head pipes within 6 months and I did NOT neglect them! The welds were crappy and I had to bend some things to get them to fit. Never again.
Now, I really don't know what's available for the Magna, not really into cruisers all that much, but if you can get anything from Vance and Hinz, Yoshimura, M4, Akrapovic, D&D, you'd be a lot more satisfied with it. Most of those are sport bike pipe manufactures and I've not looked at their line regards to cruisers, but I know V&H has a huge line of quality cruiser stuff. If you can get it in stainless or titanium, it'll hold up far better to the elements. I live next to a salt water bay, so that's always big on my mind for pipes. I just do not like chrome, especially on pipes.